i  volcanoes  of  the  Kula  basin  in 

y  Stephens  Y-,  ashing  ton 


8S3H 


THE  GIFT  OF 

FLORENCE  V.  V.  DICKEY 

TO  THE 

UNIVERSITY  OF  CALIFORNIA 
AT  LOS  ANGELES 


THE  DONALD  R.  DICKEY 

LIBRARY 
OF  VERTEBRATE  ZOOLOGY 


The  RALPH  D.  REED  LIBRARY 


DEPARTMENT  OF  GEOLOGY 

UNIVERSITY  OF  CALIFORNIA 

LOS  ANGELES,  CALIF. 


THE  VOLCANOES  OF  THE  KULA 
BASIN  IN  LYDIA 


3Inawgut:al  J^f 


•FOR  THE  ATTAINMENT  OF  THE 

DEGREE   OF  DOCTOR    OF    PHILOSOPHY 

AT  THE 

UNIVERSITY  OF  LEIPZIG 


PRESENTED  BY 

HENRY    STEPHENS    WASHINGTON 

OF 

NAVESINK,  N.  J.,  U.  S.  A. 
July  26,  1893 


NEW  YORK 

ROBERT  DRUMMOND,  PRINTER 
1894 


THE  VOLCANOES  OF  THE   KULA 
BASIN  IN  LYDIA 


Inaugural 


FOR   THE   ATTAINMENT   OP   THE 


DEGREE    OF  DOCTOR    OF    PHILOSOPHY 


UNIVERSITY  OF   LEIPZIG 


PRESENTED  BY  f 

HENRY    STEPHENS    WASHINGTON 

«  OF 

NAVESINK,  N.  J.,  U.  S.  A. 
July  26,  1893 


NEW  YORK 
ROBERT   DRUMMOND,   PRINTER 

1894 


Geol,,,,, 
Library 

I 


INTRODUCTION. 


Ix  the  course  of  the  writer's  studies  at  the  "University  of  Leipzig 
during  the  winter  semester  of  1891-92,  the  volcanic  district  in  Asia 
Minor  known  to  the  ancients  under  the  name  of  the  Katakekau- 
mene  in  Lydia  was  spoken  of  by  Prof.  Dr.  Zirkel  as  promising  a 
good  field  for  petrographical  work,  and  it  was  decided  to  visit 
it  in  the  spring.  Accordingly,  after  a  two  months'  stay  in  Greece, 
the  writer  was  able,  in  April,  to  pass  over  "into  Asia  Minor,  where 
nearly  two  weeks  were  spent  in  visiting,  with  friends,  sites  of  archaeo- 
logical interest.  Unfortunately,  an  important  matter  unexpectedly 
called  the  writer  away,  leaving  only  eight  days  for  an  examination 
of  the  region  named  above.  The  shortness  of  the  time  is  re- 
gretted, but  it  is  hoped  to  visit  the  place  again  in  the  spring  of 
1894,  when  a  map  will  be  drawn,  and  as  complete  an  exploration 
of  the  whole  region  as  possible  be  made.  In  the  meanwhile  this 
paper  will  give  a  short  preliminary  sketch  of  part  of  the  district, 
and  the  results  of  a  petrographical  examination  of  the  rocks 
collected,  undertaken  in  the  Mineralogical  Institute  of  the  Univer- 
sity of  Leipzig,  under  the  guidance  of  Geheimrath  Prof.  Dr. 
Zirkel,  to  whom  the  writer  desires  to  return  his  warmest  thanks 
and  to  express  his  sense  of  the  great  obligations  he  is  under  for 
the  constant  and  invaluable  aid  and  advice  and  the  never-failing 
kindness  shown  him. 


550894 


THE   VOLCANOES   OF   THE   KULA   BASIN 
IN   LYDIA. 


GENERAL  DESCRIPTION. 

THE  chief  town  of  the  district,*  and  the  one  that  the  writer 
made  his  headquarters,  is  Kula,f  the  seat  of  a  large  carpet  industry 
a  place  with  12,000  inhabitants,  of  whom  8500  are  Turks,  and  the 
rest  Greeks.  It  is  situated  in  38°  33'  N.  Lat.  and  28°  42'  E.  Long., 
in  the  eastern  part  of  the  vilayet  (province)  of  Aidin,  or  what  was 
anciently  called  Lydia,  some  125  kilometres  E.  by  N.  of  Smyrna,  in 
a  straight  line.  It  is  reached  by  travelling  by  rail  to  Ala  Shehir 
(ancient  Philadelphia),  a  trip  of  169  kil.  (6^  hours),  where  one 
spends  the  night.  From  Ala  Shehir  one  drives  over  a  good  road 
across  the  Konfirja  Mountains,  and  reaches  Kula  in  about  5  hours. 
As  the  only  regular  accommodation  for  travellers  is  a  very  dirty, 
noisy,  and  public  khan,  one  must  either  bring  letters  to  some  of  the 
inhabitants,  or  trust  to  someone's  hospitality  for  a  lodging.  The 
writer  was  most  kindly  received  and  courteously  treated  by  a  Greek 
named  Haji  Moise,  who  several  times  acted  as  guide  to  various 
places  of  interest,  and  to  whom  the  writer  wishes  to  return  his 
thanks.  It  may  be  remarked  that  a  knowledge  of  modern  Greek  or 

*  As  some  Turkish  topographical  words  will  be  used  in  the  course  of  this 
and  other  papers,  the  following  short  vocabulary  will  be  found  of  use : 
Bunndr  =  Spring.  Chai  =  River.  Dag  =  Mountain.  Ool  —  Lake.  Hissdr  = 
Castle.  Kale  —  Fortress.  Koi=  Village.  Koprii  =  Bridge.  Shehir  =  City. 
Sit  =  Water,  Brook.  TasJi  =  Rock.  Tepe  =  Hill. 

The  plural  is  formed  by  adding  the  syllable  lar  01  far,  according  as  the 
vowel  of  the  word  is  strong  or  weak.  The  accent  of  Turkish  words  falls  as 
a  rule  on  the  last  syllable. 

f  The  name  Kula  (also  written  Koulah)  is  derived  from  the  Turkish  Kiile  = 
a  tower.  The  Byzantine  fortress  of  Opsikion  stood  on  this  site.  Cf.  Ramsay. 
Hist.  Geog.  As.  Miu.  p.  123. 

5 


6  THE   VOLCANOES    OF  THE   KTJL.A   BASIN   IN    LYDIA. 

Turkish  is  almost  indispensable,  though  one  can  get  along  with  a 
dragoman. 

Ancient  History. — The  extant  historical  notices  of  the  region 
are  extremely  scanty,  being  confined  practically  to  three  writers. 
Strabo  (born  ca.  54  B.C.),  in  his  famous  geography,  is  the  first  to 
mention  it.  He  speaks  as  follows  :*  "  After  these  (Mysia  and 
Philadelphia)  is  the  country  called  Katakekaumene  (Burnt 
Country),  500  stadia  f  in  length  and  400  in  breadth,  which  belongs 
to  either  Mysia  or  Maeonia,  for  it  is  ascribed  to  both;  .  .  .  entirely 
bare  of  vegetation,  except  for  the  vine  which  produces  the 
Katakekaumene  wine,  which  is  not  inferior  to  any  other  of  the 
famous  wines.!  The  appearance  of  the  plains  is  ashy,  and  of  the 
mountainous  part  stony  and  black,  as  if  from  a  conflagration.  § 
Some  represent  this  as  having  happened  from  thunderbolts  and 
lightning  strokes,  and  do  not  hesitate  to  make  it  the  scene  of  the 
fable  of  Typhon.  .  .  .  But  it  is  unreasonable  to  suppose  that 
so  large  a  district  wassail  at  once  consumed,  by  lightning  and 
thunderbolts  ;  it  is  more  natural  to  think  that  the  effect  was 
produced  by  fire  generated  in  the  soil,  the  source  of  which  is  now 
exhausted.  And  three  pits  are  shown,  which  they  call  blow-holes 
((f>v<ra(i),  distant  40  stadia  from  each  other.  Kough  hills  lie  over 
these,  which  have  probably  been  heaped  together  from  the  glowing 
masses  blown  up.  ...  " 

Vitruvius  (de  Archit.  n.  6),  in  speaking  of  cements  and 
mortar,  says  that  this  region  and  JEtna  are  the  two  whence  is 
obtained  suitable  pumice,  or  volcanic  ashes,  for  mixing  with  lime. 
He  quotes  the  presence  of  hot  springs  as  evidence  of  their  volcanic 
origin. 

From  Metaphrastes,||  a  ^Q  Byzantine  writer,  we  learn  that  the 
district  was  called  Decapolis,  and  he  speaks  of  it  as  having  been 
burned  with  fire. 

*  Strabo,  xm,  4,  11. 

t  The  Stadion  was  about  one  eighth  of  an  English  mile.  As  Hamilton  says, 
Strabo  has  evidently  overrated  the  extent  of  the  district,  its  real  length  being 
about  18  miles,  and  its  breadth  7  or  8. 

$  Pliny  (N.  H.  xiv.  75)  mentions  this  wine. 

§  The  modern  Turks  recognize  the  igneous  origin  of  these  lava  beds  in  their 
name  for  them,  Janyk  Tosh  =  Burnt  Rock. 

JActn,  Pionii,  in  Acta  Sanctorum,  Febr.  1,  p.  43.  "Vos  Decapolini, 
Lydise  regionem,  igne  combustam,  videtis."  Cf.  Ramsay,  op.  cit.  pp  123,  132, 
432. 


THE   VOLCANOES    OF   THE    KULA    BASIN   IN   LYDIA.  7 

None  of  these  writers  speak  of  volcanic  eruptions  as  taking 
place  in  their  day,  though  Strabo  evidently  thinks  that  such 
eruptions  have  produced  the  three  principal  volcanoes.  He  speaks 
in  another  place  of  Philadelphia  as  being  "full  of  earthquakes," 
so  much  so  that  walls  were  overthrown,  great  damage  done,  and 
few  of  the  inhabitants  lived  in  the  city.  We  may,  however,  take 
it  for  granted  that  there  has  been  no  eruption  in  historical  times, 
though  the  history  of  Asia  Minor  is  so  imperfect  that  the  record 
of  such  an  occurrence  may  not  have  come  down  to  us.  With  the 
exception  of  a  few  hot  springs,  to  be  mentioned  later,  there  are 
no  indications  of  volcanic  action  going  on  at  present,  and  I  could 
hear  of  no  traditions  to  the  effect  of  an  eruption  having  been  seen 
by  the  present  inhabitants  or  their  ancestors. 

Modern  Descriptions. — The  chief  modern  writers  who  have  de- 
scribed the  region  from  a  geological  point  of  view  are  W.  J.  Hamil- 
ton,* H.  E.  Strickland.f  P.  de  Tchihatcheff,J  and  C.  Texier.§  The 
two  former  in  1836,  and  the  first  alone  in  1837,  travelled  across  the 
region  and  described  it.  The  third,  some  years  later,  also  visited 
it,  but  chiefly  confines  himself  to  quoting  the  other  two  and  con- 
firming their  observations.  Texier's  account  is  also  based  chiefly 
on  Hamilton's  work,  and  partially  on  a  personal  visit  to  the  Kula 
Basin.  The  western  portion  he  describes  by  hearsay.  It  is  read- 
able but  short,  and,  as  he  was  not  a  geologist,  at  fault  in  some 
particulars.  As  the  two  earlier  writers  give  a  very  good  idea  of  the 
plan  and  structure  of  the  region,  we  cannot  do  better  than  make  a 
few  quotations  from  their  joint  paper: 

"The  tertiary  deposits  in  this  basin  of  the  Katakekaumene 
consist  of  horizontal  beds  of  white  limestone  passing  downwards  (in 
the  northern  part  of  the  basin)  into  volcanic  tufa.  The  limestones 
have  b.een  deeply  denuded  by  the  Hermus  (Gediz  Cha'i)  and  its 
tributaries,  and  now  form  a  series  of  lofty  plateaux.  .  .  . 

"  The  Catacecaumene  is  described  .  .  .  as  a  tertiary  lacustrine 
basin,  surrounded  by  hills  of  schistose  rocks.  It  is  drained  by 


*  Hamilton,  Researches  in  Asia  Minor,  Pontus  and  Armenia.  London, 
1842.  I.  136-140  and  n.  130-150. 

f  Hamilton  and  Strickland,  On  the  Geology  of  the  Western  Part  of  Asia 
Minor.  Trans.  Geol.  Soc.,  3d  Ser.,  vi.  81. 

$  Tchihatcheff,  Asie  Mineure.  Pt.  IV.  Geologic.  Paris,  1867.  i.  7. 
211  ff. 

§  Texier,  Asie  Mineure.     Paris,  1882.     pp.  272-275. 


8  THE   VOLCANOES   OF  TUB   KULA    BASIN   IN   LYDIA. 

the  Hermus,  which  escapes  at  Adala  through  a  narrow  gorge  in  the 
schistose  formation,  the  closing  of  which  to  a  sufficient  height 
would  again  convert  the  upper  country  into  a  lake.  Numerous 
volcanic  eruptions  have  taken  place  among  the  older  rocks,  which 
formed  the  southern  margin  of  the  basin;  and  streams  of  lava, 
flowing  from  these  foci,  have  overspread  the  lacustrine  deposits. 

"  The  outbursts  of  volcanic  matter  appear  to  be  referable  to 
three  great  periods.  How  long  may  have  been  their  duration,  or 
how  long  the  interval  of  repose  between  each,  is  buried  in  the  tomb 
of  time.  All  that  we  can  now  assert  is  that  long  intervals  must 
have  passed  between  each  eruption ;  and  that  the  latest  eruption 
occurred  antecedently  to  the  commencement  of  traditional  or  au- 
thentic history. 

' '  The  oldest  series  of  eruptions  took  place  at  a  time  when  the 
bed  of  the  lake  presented  a  nearly  level  and  unbroken  surface,  and 
before  the  first  commencement  of  the  excavation  of  the  present 
valleys  ;  for  the  basaltic  rocks  of  that  period  invariably  form  the 
capping  of  the  vast  horizontal  plateaux  of  tertiary  lacustrine  lime- 
stone. .  .  .  The  eruptions  of  the  second  period  were  subsequent 
to  the  drainage  of  the  lake,  and  to  the  excavation  of  deep  valleys 
in  the  lacustrine  deposits.  Those  of  the  third  period  are  still  more 
recent,  and  are  distinguished  by  their  entire  identity  of  character 
with  volcanoes  now  in  action." 

As  I  did  not  visit  any  of  the  first-period  basalt  sheets,  and  have 
no  specimens,  we  will  here  omit  their  description.  To  continue  the 
quotation  : 

"To  the  second  period  of  volcanic  action  we  refer  the  numer- 
ous conical  hills  of  scoriae  and  ashes  which  cover  the  schistose 
ridges  on  the  south  of  the  lacustrine  formation.  The  range  of 
mica  schist  and  marble,  which  runs  from  east  to  west  on  the  south 
of  Koola,  sends  off  three  nearly  parallel  ridges  towards  the  north, 
and  may  therefore  be  compared  to  the  letter  E.  The  volcanic  cones 
of  the  second  period  are  scattered  along  this  principal  ridge  and  its 
three  lateral  branches,*  and  many  streams  of  lava  may  be  traced 
flowing  from  them,  and  descending  the  valleys  of  denudation  in  the 
lacustrine  formation  towards  the  Hermus. 

*  There  are,  as  seen  on  the  map,  a  number  of  exceptions  to  this  rule,  where 
second-period  cones  have  been  formed  in  the  basin  between  the  schistose 
ridges. 


THE   VOLCANOES   OF  THE   KULA   BASIN    IN    LYDIA  9 

"  The  volcanic  products  of  this  period  are  distinguished  by  the 
smoothness  of  their  outlines,  and  by  the  vegetation  which  clothes 
their  surfaces.  The  cones  of  scoriae  are  all  low  and  flat,  rising  at 
an  angle  of  about  20° ;  their  craters  have  either  disappeared,  or  are 
marked  only  by  small  central  depressions,  and  all  their  asperities 
seem  to  have  been  smoothed  down  by  time.  The  scoriae  which 
form  them  are  sufficiently  decomposed  to  admit  of  cultivation,  and 
they  are  almost  invariably  covered  with  vineyards,  producing  the 
Catacecaumene  wine,  celebrated  from  the  time  of  Strabo  to  the 
present  day.  The  streams  of  lava  which  have  flowed  from  them  are 
level  on  the  surface  and  covered  with  turf. 

''The  volcanic  cones  of  both  the  second  and  third  periods  have 
been  poured  forth  since  the  excavation  of  the  valleys  in  the  lacus- 
trine formation ;  but  their  diversity,  in  point  of  age,  is  marked  no 
less  by  their  order  of  superposition  than  by  the  great  difference  in 
their  state  of  preservation.  The  cones  of  the  third  period  have  all 
the  features  of  volcanoes  now  in  action.  They  rise  at  an  angle  of 
30°  or  32°,  and  the  ashes  and  scoriae  which  compose  them  are  so 
loose  as  to  render  the  ascent  laborious.  A  few  straggling  shrubs 
and  plants  are  the  only  vegetation  they  produce  ;  and  the  lava 
which  lias  flowed  from  them  is  as  rugged  and  barren  as  the  latest 
product  of  zEtna  or  Vesuvius. 

"  The  volcanoes  of  this  third  period  are  only  three  in  number,* 
and  are  nearly  equal  in  size.  They  stand  in  a  nearly  straight  line 
from  W.  by  N.  to  E.  by  S.,  and  at  a  distance  of  about  six  miles 
from  each  other.  It  is  remarkable  that  each  of  them  rises  in  the 
centre  of  one  of  the  small  alluvial  plains  which  alternate  with  the 
three  schistose  ridges  before  described,  therein  differing  from  the 
cones  of  the  second  period,  all  of  which  stand  upon,  or  near,  those 
ridges." 

The  above  general  description  will  give  the  reader  a  tolerably 
clear  idea  of  the  whole  district.  The  shortness  of  my  stay  pre- 
vented me  from  doing  more  than  studying  partially  the  eastern- 
most, or  Kula,  basin,  with  one  trip  to  beyond  the  Gediz  Chai  on 
the  north,  and  another  to  Griilde  on  the  northwest.  Other  hin- 
drances were  the  difficult  nature  of  the  ground,  want  of  a  map, 
and  the  great  heat. ,  Some  time  was  also  spent  in  archaeological 
investigations. 

*  The  cone  of  Kara  Tepe  must  be  added  to  this  number,  and  there  are 

perhaps  others  farther  west. 


10        THE   VOLCANOES   OF  THE   KULA    BASIN   IN   LYDIA. 

Tlie  Kula  Basin. — A  more  particular  description  of  the  Kula 
Basin  may  now  be  given,  for  which  the  accompanying  sketch  map 
has  been  drawn.*  Cf.  Plate  I. 

The  geological  structure  of  this  basin  is  seen  in  the  section  (Fig. 
1)  which  runs  from  Hammamlar  to  the  Konurja  Mts.  From  this 
it  will  be  seen  that  the  mountain  range  to  the  south  of  Kula,  and 
the  rocks  underlying  the  basin  itself,  are  hornblende-schist  and 
mica-schist.  The  former  forms  the  lower  strata  and  constitutes 
the  greater  part  of  the  Konurja  Mts.  At  Azi  Koi  the  strata  are 
almost  horizontal,  but  farther  up  the  southern  slope  of  the  ridge 
,.  (about  an  hour  below  the  top  of  the  pass)  they  dip  30°  towards  the 
N.W.  Near  Kula  we  find  mica-schist  overlying  this  in  almost 
horizontal  strata,  with  here  and  there  veins  of  marble,  f  This 
marble  is  often  very  white,  and  can  be  quarried  in  large  masses, 


^-HORNBLENDE  SCH1STES3-M1CA  SCHIST  O-UMESTONE^-PPfR.BWALTE]3'*'«PtRBASALT  •i=S«'PER.BA5ALT 
FIG.  1. 

supplying  the  material  for  the  buildings  of  the  ancient  towns  of 
the  district,  and  whose  remains  we  now  meet  with  in  some 
quantity. 

What  the  age  of  these  crystalline  schists  is  it  is,  at  present,  al- 
most impossible  to  say.  Hamilton  and  Strickland  think  they  are 
pre-cretaceous,  and  "provisionally  "  refer  them  "  to  the  primary  or 
transition  epoch."  Tchihatcheff  J  also  "  provisionally "  places 
the  mica-schists  and  allied  rocks  of  Asia  Minor  in  the  Devonian  or 
Carboniferous  Period.  From  their  geographical  proximity  and 
similarity  of  characteristics,  it  is  possible  that  they  belong  to  the 
same  age  as  the  great  schistose  formations  of  Greece.  This,  how- 
ever, is  uncertain  and  we  must  leave  the  queston  an  open  one. 

*  Hamilton  and  Strickland  (loc.  cit.)  give  a  map  of  the  whole  district  with 
some  sections,  which,  however,  does  not  seem  to  be  very  accurate.  The  pres- 
ent map,  also,  does  not  pretend  to  any  great  accuracy.  It  has  been  compiled 
partly  from  Hamilton's  map  and  partly  from  my  own  notes.  Lack  of  time 
did  not  allow  of  my  making  a  survey. 

fCf.  Tchihutcheff,  op.  cit.  p.  544. 

\  Op.  cit.  p.  476. 


THE   VOLCANOES   OF   THE   KULA   BASIN   IN   LYDIA.         11 

The  limestone  through  which  the  basalt  of  the  first  period 
poured  is  called  tertiary  by  Hamilton  and  Strickland,  and  there 
seems  no  reason  for  doubting  the  correctness  of  this  opinion, 
though  no  fossils  were  found  in  it.  That  the  third  and  second 
periods  of  eruption  were  post-tertiary  there  is  no  doubt  whatever, 
to  judge  from  their  fresh  state  of  preservation.  While  the  form  of 
the  second-period  cones  is  somewhat  degraded,  yet  the  outlines  of 
many  of  them  are  still  sharp  and  their  craters  very  distinct,  while 
the  third-period  cones  have  apparently  suffered  hardly  at  all  from 
atmospheric  action.  Hamilton  and  Strickland  seem  inclined  to  ac- 
count for  the  more  denuded  state  of  the  second-period  cones  by 
supposing  them  to  have  been  formed  by  a  subaqueous  eruption. 
But  they  themselves  admit  the  difficulties  of  this  view,  and  it 
seems  hardly  worth  while  to  dwell  upon  it.  The  limits  and  aims 
of  the  present  paper  do  not  admit  of  further  remarks  on  the  general 
geology  of  the  region,  and  we  can  now  turn  to  the  volcanic  cones 
and  their  lava  streams. 

Second-Period  Cones.  —  The  second  -  period  cones  of  the  Kula 
Basin  are  as  follows  :  Southeast  of  Kula  Devlit  (the  principal  third- 
period  volcano  of  the  basin),  and  joined  to  it  by  a  ridge  of  lava,  is 
the  large,  breached,  crater  cone  of  Piresik  Devlit,*  about  150  m. 
high,  with  its  open  side  to  the  southwest,  from  which  has  flowed  a 
lava  stream,  now  covered  by  the  Kula  Devlit  outpours.  This  pre- 
sents all  the  characteristics  of  second-period  cones  mentioned  by 
Hamilton.  The  outer  slope  is  at  an  angle  of  20°-34°,  and  the  inner 
slopes  of  the  crater  are  planted  in  vines.  To  the  southeast  stretch 
a  line  of  three  small  cones,  Yele  Tepeler  (Hills  of  the  Horse's 
Mane),  and  to  the  northeast  are  also  two  small  cones  spoken  of 
later.  About  three  kilometres  to  the  east  is  Gol  Dag  (Lake 
Mountain),  a  large  unbreached  crater  cone,  and  beyond  this 
another  second-period  cone.  Two  and  a  half  kilometres  to  the 
north-northwest  of  Kula  Devlit  rises  the  cone  of  Boz  Tepe  (Ice 
Hill),  breached  on  the  south,  and  sending  a  stream  of  lava  around 
itself  to  the  north.  Some  other  second-period  cones  are  shown  in 
the  map,  but  the  only  remaining  one  of  present  interest  is  Ai 
Tepesi  (Moon  Hill),  situated  on  the  schistose  ridge  running  north 
and  south,  northwest  of  Kula  and  south  of  Guide.  This  volcano 
has  sent  a  stream  of  lava  about  three  kilometres  to  the  southeast, 

*  Shown  in  Plate  II,  1,  to  the  right  of  Kula  Devlit. 


12        THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA. 

its  end  being  near  a  spring  of  cold,  clear  water,  on  the  road  to 
Menne. 

TJiird-Period  Cones. — But  the  chief  feature  of  the  landscape  and 
main  point  of  interest  of  the  Kula  Basin  is  the  volcano  (cf.  PI.  II, 
Fig.  1)  called  Kula  Devlit  *  by  the  Turks  and  Kai'meni  Devlit  by  the 
Greeks. f  This  cone  has  a  height  of  165  metres  above  the  plain  below, 
or  885  J  above  sea-level.  Its  sides  slope  at  an  angle  of  30°  30.'  The 
ascent,  owing  to  the  lapilli  and  scoriae  with  which  it  is  covered,  is 
very  fatiguing,  but  the  summit  once  gained  we  get  a  splendid  and 
striking  view  over  the  whole  of  the  Kula  Basin.  To  the  north  our 
range  is  bounded  by  the  Demirji  Dag,  with  glimpses  of  the  Gediz 
Cha'i  flowing  from  the  northeast,  to  the  east  the  hills  that  shut  out 
the  view  of  Ushak,  on  the  south  the  Kouurja  Dag,  which  we 
crossed  coming  from  Ala  Shehir,  and  to  the  west  a  low  ridge 
studded  with  second-period  cones,  and  with  Kara  Devlit  showing 
beyond  it.  At  our  feet  lies  a  field  of  black  lava  stretching  to  the 
Gediz  on  the  north,  with.the  second-period  cones  already  described, 
and  beyond  its  borders  the  green  cultivated  fields  of  the  alluvial 
deposits,  forming  a  striking  and  wonderful  contrast  to  the  barren 
blackness  of  the  lava,  and  which  I  can  only  compare  for  sharpness 
of  contrast  with  the  view  of  the  Nile  Valley  from  the  cliff  at 
Assiut,  or  the  top  of  the  Great  Pyramid.  Immediately  to  the 
south  lies  the  picturesque  town  of  Kula,  its  white  houses  and  nu- 
merous minarets  forming  a  very  pretty  picture  against  the  black  and 
green  background.  To  the  northwest  we  get  a  glimpse  of  the  vil- 
lage of  Giilde/and  to  the  east  lies  Koros  Koi.  For  picturesqueness 
indeed  some  of  the  views  about  the  Kula  Basin  surpass  those  that 
I  have  seen  in  similar  regions,  the  oriental  features  adding  a  char- 
acter which  is  lacking  elsewhere.  The  cone  itself  is  almost  bare  of 
vegetation,  except  for  a  few  wild  oats,  a  little  grass,  and  some  small 
blue  flowers  on  the  southern  rim  of  the  crater,  which  is  about  ten 
metres,  wide,  and  on  whose  highest  point  is  a  small  Greek  chapel. 
* , 

•Hamilton  (op.  cit.)  calls  this  Kara  Devlit.  At  the  present  day  this  is 
the  name  of  the  coue  near  Menne. 

t  The  word  "devlit"  means  properly  "state,  government"  (Redhouse, 
Turk.  Diet.,  «.  •».  p.  571).  At  Kula  it  seems  to  have  the  signification 
of  "mountain."  The  authors  quoted  all  translate  it  ' '  inkstand,"  but  for  this 
I  could  find  no  authority.  Cf.  v.  Diest  (Von  Pergarnon  .  .  .  zum  Poutus, 
Peterm.  Mitth.  Erg.-Heft  94,  p.  40),  who  likewise  translates  "inkstand." 

J  Hamilton  makes  it  867.     Both  determinations  are  barometric. 


THE   VOLCANOES   OF   THE*  KULA   BASIN   IN   LYDIA.        13 

The  crater  of  Knla  Devlit  is  some  three  hundred  metres  across, 
oval  in  shape  and  double,  a  smaller  and  later  crater  occupying  the 
southwest  corner  of  the  larger,  the  ejections  from  which  have 
helped  to  raise  the  southern  rim  to  its  present  greater  height.  The 
larger  crater  wall  is  quite  perfect  except  at  the  east  side,  where  it 
has  been  broken  down  by  a  comparatively  early  stream,  the  surface 
of  which  is  almost  invisible  owing  to  the  accumulation  of  lapilli  and 
sand  over  it.  The  inner  walls  of  the  two  craters,  which  slope  at  an 
angle  of  30°,  are  composed  of  loose  lapilli,  with  here  and  there 
large  masses  of  scoria  and  vesicular  lava,  in  some  of  which  were 
found  inclosures  of  rock  brought  up  from  below.  The  lapilli  and 
scoriae  show  few  signs  of  decomposition,  due  doubtless  to  the  fact 
that  the  rain-water  soaks  rapidly  through  them  owing  to  their 
porous  character.  Probably  owing  to  the  same  cause  there  are  no 
gullies  affording  natural  sections  where  the  structure  of  the  crater 
walls  can  be  studied.  There  seems  not  much  reason,  however,  for 
doubting  that  the  cone  is  entirely  a  cinder  cone,  with  no  lava-flows 
in  it  except,  perhaps,  near  the  base. 

The  lava  streams  of  Kula  Devlit  have  all,  as  far  as  can  be  seen, 
broken  out  beyond  the  flanks  of  the  cone,  with  two  exceptions,  one 
the  older  stream  mentioned  above,  and  the  other  a  short  ridge  of 
lava  on  the  south  flank,  near  Piresik  Devlit.  The  main  streams 
form  two  large  lava  fields,  one  to  the  south  and  southwest,  and  the 
other  to  the  north  and  northeast,  as  shown  on  the  map. 

The  former  field  is  seen  to  belong  to  at  least  two  distinct  periods 
of  activity.  To  the  first  belong  what  may  be  called  "  knolls  "; 
rough  and  jagged  bosses  and  hummocks  of  rock,  of  which  over 
thirty  were  counted  to  the  southeast  of  Kula  Devlit.  These  vary 
form  3  to  20  m.  high,  above  the  later  stream,  and  15  to  60  m.  broad 
at  their  base.  The  later  lava  stream  flows  round  them,  leaving  gen- 
erally some  space  between.  These  "  knolls  "  seem  not  to  be  cones 
or  domes,  marking  special  local  eruptions,  but  are  apparently  merely 
masses  of  lava  which  have  been  heaped  up  in  the  course  of  flow  of 
the  stream  beneath.  What  cause  produced  such  peculiar  localiza- 
tion of  the  crust  and  lava  I  cannot  well  say.  In  some  cases  they 
seemed  solid  hills  of  lava,  a  few  scoriaceous  above,  and  more  com- 
pact below,  but  split  by  clefts  and  crevices,  some  of  which  are  20  m. 
deep,  and  at  the  bottom  of  which  are  seen  the  bones  of  sheep,  etc., 
brought  there  by  wolves  and  jackals.  In  the  crevices  and  hollows 
of  these  "  knolls  "  grow  some  tufts  of  grass  and  flowers,  and  occa- 
sionally a  shrub  or  a  wild  fig-tree.  Cf.  PI.  II,  Fig.  2. 


14    THE  VOLCANOES  OF  THE  KULA  BASIN  IN  LYDIA. 

The  latest  flow  forms  a  nearly  level  *  plain  of  black  lava,  whose 
surface  is  extremely  rough  and  jagged — the  "cindery"  surface 
characteristic  of  viscous  streams  f  (one  exception  to  this  is  noticed 
later).  A  coating  of  dark-green  moss  has  grown  over  this,  making  the 
jagged  edges  still  more  slippery,  and  walking  still  more  difficult. 
Apart  from  this  moss  no  vegetation  whatever  is  seen  on  this  field. 
To  the  southeast  the  latest  flow  ends  east  of  the  northeast  corner 
of  the  town  of  Kula,  but  some  "  knolls"  are  to  be  seen  projecting 
above  the  alluvial  deposit  for  some  distance  farther  south.  In 
places  also  two  streams  can  apparently  be  distinguished,  one  above 
the  other,  the  lower  much  more  compact  and  with,  in  some  in- 
stances, a  columnar  structure.  This  columnar  struture  is  also  to 
be  seen  in  the  lower  part  of  the  upper  streams,  in  a  few  places. 
The  columns  are  5-25  cm.  thick  and  25-40  cm.  long,  irregular  in 
shape,  and  radiating  perpendicularly  to  the  uneven  surface. 

The  southwest  stream  of  Kula  Devlit,  which,  while  petrographi- 
cally  apparently  distinct/  yet  shows  no  marked  line  of  demarcation, 
runs  to  within  a  few  metres  of  the  foot-hills  of  the  mountain  ridge, 
leaving  barely  room  enough  for  the  road  to  Guide  and  Kavakly. 
The  stream  shows  fewer  "knolls,"  and,  if  anything,  is  less  scoria- 
ceous  than  the  southeast  stream,  but  is  not  as  deep — the  latter  having 
flowed  into  the  channel  of  a  small  stream  to  the  east  of  the  site  of 
Kula,  choking  it  up  and  giving  rise  to  a  small  lake. 

The  largest  stream  of  all  is  the  north  stream,  which,  starting 
from  the  east^side  of  Kula  Devlit,  flows  to  the  Gediz  Chai',  a  dis- 
tance of  about  10  km.  It  is  at  first  confined  on  the  south  by  two 
small  second-period  cones,  and  farther  on  it  seems  to  have  followed 
a  stream  bed  to  the  Gediz,  which  river  it  turned  out  of  its  course 
to  some  extent,  and  now  at  its  northern  extremity  forms  a  perpen- 
dicular cliff  of  lava  10-20  m.  high.  The  upper  part  is  vesicular  for 
about  two  metres,  the  next  six  or  seven  are  columnar,  and  the  lower 
part  very  compact  and  hard.J  There  seem  to  be  some  "knolls" 
also  in  this  lava  field,  but  I  went  very  little  over  its  surface.  This 
stream  seems  to  belong,  on  petrographical  grounds,  to  the  same 


*  The  lava  field  at  the  base  of  Kula  Devlit  is  30  m.  above  the  level  at  the 
town,  giving  a  slope  of  about  1.5  per  cent. 

f  Cf.  Geikie  Text-book  of  Geology,  1893,  217. 
\  Cf.  Ham.  and  Strick.,  op.  cit. 


THE   VOLCANOES   OF  THE   KULA    BASIN   IN   LYDIA.         15 

period  as  the  later  southeast  stream,  and  at  the  Gediz  Bridge  (so- 
called  Bogaz  Kopriisii)  there  underlies  it  a  second-period  stream. 

The  only  large  third-period  cone  besides  Kula  Devlit  is  one  about 
1.6  km.  W.N.W.  of  the  latter,  called  Kara  Tepe  (Black  Hill). 
This  is  a  scoria  cone,  60  m.  high,  breached  on  the  west  side,  and 
showing  a  stream  of  lava  which,  after  flowing  a  short  distance  west, 
turns  north,  then  northeast,  and  runs  round  a  nameless  breached 
cone  near  Boz  Tepe.  This  crater  and  lava  stream  represent  by  far 
the  youngest  eruption  of  all,  judging  from  its  state  of  preservation. 
The  scoria  is,  as  the  name  of  the  cone  denotes,  mostly  black  and 
in  a  wonderfully  fresh  and  undecomposed  condition,  the  thinnest 
threads  and  partition-walls  being  still  fresh  and  whole.  To  the 
east  of  Kara  Tepe  is  a  small  west  ward -flowing  stream,  with  the 
''ropy"  surface  characteristic  of  rather  fluid  streams.  As  some  of 
the  "knolls"  show  the  same  character  and  are  similar  to  the  lava 
of  this  stream  petrographically,  this  short  stream  may  be  assigned 
to  the  "knoll"  outflow  of  Kula  Devlit. 

To  the  north  of  Kula  Devlit  rise  numerous  small  cones  and 
domes,  20-30  m.  high,  generally  oblong,  and  many  with  their 
long  axes  pointed  toward  Kula  Devlit.  These  are  covered  with 
scoriae  and  lapilli,  and,  as  they  are  small  and  show  no  crater  de- 
pression, are  held  to  be  domes  (Kupperi).  They  arise  in  a  field  of 
older  lava,  smooth  and  covered  with  sand  and  lapilli,  but  belong 
themselves  to  the  third  period,  and  perhaps  to  the  latter  part  of  it. 

Alluvium,  etc. — The  town  of  Kula  lies  at  the  north  edge  of  a 
small,  fertile  triangular  plain,  690  m.  above  sea  level.  As  shown 
by  a  well-digging,  spoken  of  later,  the  town  is  built  chiefly  on  an 
old  second  period  stream,  perhaps  from  Piresik  Devlit,  the  north- 
ern part  of  the  town  being  on  the  edge  of,  and  partly  built  on,  the 
southern  Kula  Devlit  streams.  On  the  east  flows  the  small  stream 
of  Kula  Su,  which  starting  as  a  brook  in  the  Konurja  Mountain, 
runs  northerly  and  empties  into  a  marshy  lake  formed  by  the 
damming  of  the  brook  by  the  southeast  lava  stream. 

The  alluvial  deposit  on  this  small  plain  is  fertile  but  not  very 
deep.  A  similar  plain  lies  between  the  north  lava  stream  and  the 
easterly  range  of  schist. 

In  the  lava  bed  itself  no  springs  are  found,  though  at  two  or 
three  places  one  finds  large  jars  kept  filled  with  fresh  water  for  the 
benefit  of  the  thirsty  traveller — a  charitable  custom  of  the  Turks. 
At  the  foot  of  the  schistose  mountains  springs  are  quite  common, 


16        THE   VOLCANOES   OF  THE   KULA    BASIN   IN   LYDIA. 

furnishing  clear,  cold  water.  At  Hamrnamlar  (the  Baths),  about 
12  kilometres  north-northeast  of  Kula,  are  two  hot  sulphurous 
springs,  of  which  the  hotter  has  a  temperature  of  58°  C.*  The 
ruins  show  this  to  have  been  the  site  of  an  ancient  town,  though  I 
found  no  traces  of  the  theatre  Hamilton  speaks  of.  About  two 
kilometres  nearer  Kula,  on  the  right-hand  bank  of  the  Gediz  (Jha'i, 
a  spring  strongly  charged  with  C02  and  having  a  very  faint  taste 
bubbles  up.  Hot  springs  and  baths  also  exist  at  Ala  Shehir. 

PETROGRAPHICAL  DESCRIPTION  OF  ERUPTIVE  ROCKS. 

The  rocks  collected  and  examined  consist  of  specimens  from 
outflows  of  the  second  and  third  periods,  mica  schist  and  horn- 
blende schist  from  the  Konurja  Mountains  to  the  south  of  Kula, 
and  one  or  two  others  to  be  described  later.  Of  these,  those  from 
the  lava  streams  are  the  most  important  and  interesting,  and  to 
them  we  shall  chiefly  devote  our  attention. 

Eruptive  Rocks. — The  eruptive  rocks  of  the  Kula  Basin  pre- 
sent many  interesting  features,  some  of  which  are  common  to  all  of 
them,  thus  forming  a  very  good  example  of  what  Vogelsaugf  first 
called  "  Geognostische  Bezirke,"  and  what  JuddJ  later  called 
"  Petrographical  Provinces."  Iddings,§  in  a  recent  paper,  speaks 
of  this  relation  as  "Consanguinity  of  Rocks,"  but  without  referring 
to  Vogelsang.  A  "  petrographical  province "  is  a  district  of  any 
extent  where  all  the  allied  rocks  possess  certain  features  in  com- 
mon, of  structure  or  chemical  or  mineralogical  composition,  etc., 
which  perhaps  may  not  be  readily  defined,  but  which  are  character- 
istic of  the  region,  distinguishing  the  rocks  of  this  district  from 
similar  rocks  of  other  districts.  One  can  compare  these  "  prov- 
inces" to  the  various  "schools"  of  painting  or  sculpture,  and  once 
the  characteristic  features  of  the  group  have  been  grasped,  one  can 
state  with  much  certainty  whether  a  given  rock  comes  from  that 
district  or  not.  The  three  authors  quoted  all  give  examples  of  this 

*  Hamilton,  Researches,  etc.  n.  p.  140. 

t  Vogelsang,  "Ueber  die  Systematik  der  Gesteinslehre,  etc."  Zeit.  d. 
deutsch.  geol.  Gesell.  1872,  p.  507. 

t  Judd,  "On  Tertiary  Gabbros,  etc.,  in  Scotland  and  Ireland."  Q.  J. 
Geol.  Soc.  1886,  p.  54. 

§  J.  P.  Iddings,  "Ou  the  Origin  of  Igneous  Rocks."  Bull.  Phil.  Soc. 
Washington,  1892,  p.  128  if. 


THE   VOLCANOES   OF   THE    KULA   BASIN   IN    LTDIA.         17 

"  consanguinity,"  of  which  Vogelsang's  are  the  best  and  most  nu- 
merous, and  the  rocks  under  present  consideration  form  another. 

This  will  be  spoken  of  again,  but  the  whole  subject  is  an  im- 
portant one,  deserving  of  more  study  and  attention  than  has 
hitherto  been  given  to  it. 

The  Kula  eruptive  rocks  are  composed  of  plagioclase,  augite, 
hornblende,  olivine,  magnetite,  and  glass,  some  with  leucite  and 
apatite,  and  a  few  secondary  minerals;  and  are  to  be  classed  as 
basalts,  more  exactly  hornblende  basalts.  Further,  they  are  to  be 
subdivided  into  hornblende-basalts  proper  and  hornblende-leucite- 
basanite.  It  was  at  first  rather  doubtful  as  to  whether  they  were  to 
be  called  andesites  or  basalts,  their  generally  andesitic  structure  and 
the  relatively  small  amount  of  olivine  inclining  one  to  the  former 
name.  But  finally  their  basic  composition,  as  determined  by  chemi- 
cal analysis,  the  character  of  the  feldspar,  the  constancy  of  the 
presence  of  olivine,  the  presence  of  leucite  in  some  of  the  streams, 
and  the  peculiar  alteration  of  the  hornblende,  hitherto  observed 
only  in  basalts,*  show  that  they  really  belong  to  the  latter  group. f 

These  basalts  are  all  porphyritic,  and  may  be  further  sub- 
divided according  to  the  structure  of  the  groundmass  into — 

(a)  Those   with    a  hypautomorphic,    granular  structure,  con- 

taining glass,  which  we  may  call  "  normal  "  basalts. 

(b)  Those  with  a  true  hyalopilitic  structure. 

(c)  Very  glassy  forms,  or  semi-vitreous  basalts. 

(d)  Tachylytes,  almost  pure  glass. 

To  the  first  belong  all  the  second-period  lavas  examined,  while 
the  third-period  flows  belong  entirely  to  the  last  three  groups.  It 
must  be  remarked,  however,  that  these  groups  shade  into  one 
another,  and  no  very  sharp  line  can  be  »drawn  between  them. 

But  before  taking  up  the  rocks  themselves  the  component 
minerals  mav  be  described. 


*  Kiicb  (Petrographie  d,  Rep.  Colombia  in  Reiss  u.  Stlibel.  Reisen  in  Sud- 
amerika,  Berlin,  1892),  having  examined  600  slides,  and  Belowsky  (Petrog. 
Rep.  Ecuador  in  ditto),  with  250  slides,  chiefly  of  hornblende-bearing  audesites, 
did  not  once  observe  this  alteration. 

t  C.  Vogelsang  (Trachyte  u.  Basalte  d.  Eifel,  Z.  d.  d.  geol.  Gesell. 
XLII.  1,  1890),  in  describing  the  hornblende-basalt  of  Briukenkopfehen,  re- 
marks that,  owing  to  the  great  deficiency  in  olivine  and  some  of  its  microscopic 
characters,  it  has  an  andesitic  character.  Cf .  Zirkel,  Basaltgcsteine,  117. 


18        THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA. 

COMPONENT  MINERALS. 

Feldspar. — The  feldspar  of  these  basalts  seems  to  be  constantly 
a  plagioclase,  but  its  quantity  is  relatively  so  small  and  the  crystals 
so  minute  that  it  was  impossible  to  effect  a  separation  of  any  of 
it  for  separate  analysis.  The  result  of  an  optical  examination 
shows,  however,  that  it  belongs  towards  the  anorthite  end  of  the 
series.  It  occurs  in  two  distinct  forms  ;  either  xenomorphic,  or 
in  well-formed  automorphic  *  crystals.  The  first  is  seen  only  in 
the  first  sub-group  mentioned  above,  the  normal  basalts,  where  it 
forms  part  of  the  groundmass,  in  leptomorphic  grains,  together 
with  colorless  glass.  In  this  form  few  of  the  sections  show 
twinning  lamellae,  and  it  is  possible  that  some  of  this  feldspar 
may  be  orthoclase,  though  the  small  percentage  of  K20  present 
makes  it  very  doubtful. 

The  second  mode  of  occurrence  is  much  more  frequent,  the 
feldspar  here  being  in'  small  laths  and  long  crystals.  These  are 
present  in  the  groundmass  of  all  the  basalts,  even  in  those  of  the 
first  group,  though  in  one  or  two  of  the  tachylytes  and  semi- 
vitreous  basalts  they  are  so  sparingly  present  as  to  be  almost 
unnoticed.  In  these  last  cases  it  seems  that  the  whole  mass 
solidified  before  the  feldspar,  which  is  one  of  the  last  of  the 
minerals  to  separate  out,  had  crystallized.  These  small  crystals 
are  colorless  and  clear,  and  twinning  lamellae  are  very  common. 
Some  twinned  lamellae  giving  almost  symmetrical  extinction  were 
measured,  the  best  giving  angles  of  31°  10'  and  29°  45',  which 
corresponds  to  a  bytownite.  In  size  they  vary  from  0.01-0.10  mm. 
in  length,  and  often  show  a  fluidal  arrangement,  together  with 
the  augite  microlites,  with  which,  on  account  of  their  small  size, 
they  are  readily  confounded. 

Augite. — The  augite  is  present  in  a  relatively  very  small 
quantity  for  a  basalt. 

Megascopically  it  is  seen  occasionally  as  crystals  from  1  to 
3  mm.  long,  of  a  clear  greenish-yellow  color,  only  to :  be  distin- 
guished by  the  eye  from  olivine  by  the  perfect  cleavage. 


*  The  terms  automorphic  arid  xenomorphic  are  used  throughout  this  paper 
Instead  of  Rosenbusch's  terms  idiom&rphic  and  allotriomorphic,  both  on  the 
ground  of  priority,  they  having  been  used  by  Rohrbach  in  1886  (Miri.  pet. 
Mitth.  vn.  1886,  p.  88),  and  because  they  are  shorter  and  etyuiologicallv  more 
correct. 


THE    VOLCANOES   OF  THE   KULA   BASIN    IN    LYDIA.         19 

Microscopically  the  largest  augites  are  colorless,  or  nearly  so, 
of  a  very  pale  fawn-gray  color,  and  are  generally  fragments, 
presenting  both  well-developed  crystallographic  planes  and  broken 
edges.  The  cleavage  is  not  well  developed. 

Those  of  a  smaller  size  are  well-formed  crystals,  from  0.1- 
0.4  mm.  long,  generally  elongated  parallel  to  the  6  axis,  but  quite 
stout  in  proportion  to  their  length.  The  planes  observed  were 
a(100),  5(010),  w(110),  w(lll),  s(lll),  p(lOl).*  They  are  either 
colorless  or  of  the  very  pale  brown  color  mentioned  above,  and 
show  no  pleochroism.  Occasionally  crystals  were  seen  with  an 
irregular  inner  core  of  a  pale  greenish  gray,  which  is  pleochroic  as' 
follows  :  c  =  dark  greenish  gray,  b  and  a  light  greenish  gray, 
c>b>tt.  The  extinction  angle  of  this  greenish  core  is  about  the 
same  as  that  of  the  colorless  border,  in 'some  cases  a  few  degrees 
more.  The  angle  of  extinction  of  the  colorless  augite  varies 
from  26°  to  43°,  most  of  the  measurements  lying  between  37° 
and  39°. 

The  augite  is  always  clear  and  does  not  show  the  prismatic 
cleavage  very  distinctly,  as  a  rule.  Inclusions  are  not  very  common, 
and  are  generally  either  clear,  mostly  brown,  glass,  or  groundmass. 
Some  crystals  were  seen  with  a  core  of  groundmass,  of  the  shape 
of  the  surrounding  crystal.  Hornblende  is  occasionally  included, 
and  magnetite  is  very  rare.  It  was  noticed  that  in  some  crystals 
in  which  the  plane  s(lll)  was  present,  small -opaque  black  grains 
were  included,  forming  a  narrow  line  parallel,  and  close,  to  this 
plane  alone,  none  of  them  being  present  m  the  rest  of  the  crystal. 

Twins  are  not  common,  and  are  almost  all  to  be  referred  to  the 
usual  twinning  plane,  a(100).  Some  "augite  stars"  and  groups 
of  crystals,  apparently  twinned  about  the  planes  y(101)  and 
W(I2'2),  were  seen,  and  one  large  augite  crystal  had  two  thin 
twinning  lamellae  at  an  angle  of  27°  with  the  cleavage  cracks, 
the  twinning  plane  being  perhaps  TF(122).f  ' 

In  many  of  the  more  glassy  varieties,  especially  in  some  of  the 
semi-vitreous  basalts,  the  augite  showed  the  well-known  "hour- 
glass "  structure,};  in  some  cases  with  interesting  modifications,  two 

*  The  crystallographic  positions,  symbols,  and  lettering  adopted  throughout 
this  paper  are  those  given  iu  Dana's  Mineralogy,  6th  Ed.  1892. 

t  Cf.  Rosenbuseh,  11.  662. 

tThis  was  first  observed  by  v.  Werveke  (Beitrag  zur  Kenutuiss  der  Lim- 
burgite.  Neues  Jahrb.  1879,  p.  488).  Descriptions  are  also  given  later  by  Ver* 


20        THE   VOLCANOES   OF  THK   KULA   BASIN   IN   LYDIA. 

of  which  are  here  shown.  In  the  one  (Plate  III,  Fig.  3)  the  section 
parallel  to  6(010)  shows  under  crossed  nicols  a  division  into  five  parts, 
i.e.,  four  border  trapezoids  and  a  central  rhomboid.  These  do  not 
extinguish  alike,  the  end  divisions  extinguishing  in  one  direction  at 
an  angle  of  42°  10',  while  the  central  and  side  divisions  extinguish 
at  just  about  the  same  angle,  but  in  an  opposite  direction.  The 
central  and  side  parts  do  not,  however,  extinguish  precisely  to- 
gether, there  being  a  barely  perceptible  difference,  and  the  effect  of 
the  whole  is  to  give  the  augite  section  the  appearance  of  a  low, 
truncated,  rhombic  pyramid.  A  rather  more  complicated,  but 
analogous,  form  is  shown  in  Fig.  4.  Dannenberg  observed  the 
same  structure  in  nepheline  basalt  from  the  Leilenkopf,  near  the 
Laacher  See,  and  gives  a  figure,  but  his  observed  extinction  angles 
differ  materially  from  mine.  In  fact  none  of  the  recorded  observa- 
tions agree  in  this  respect  among  each  other,  as  is  to  be  expected 
from  the  mode  of  formation  of  the  structure.  Besides  these  regular 
structures,  augite  crystals  were  seen  built  up  of  many,  most  irregu- 
larly-shaped, segments,  which  have  straight  edges  and  are  sharply 
defined  under  crossed  nicols,  but  most  unsymmetrically  arranged. 

A  regular  zonal  structure  is  also  frequent,  the  outer  zones  having, 
as  a  rule,  a  larger  extinction  angle  than  the  inner.  The  zones  are 
often  sharply  distinguished  from  each  other,  in  other  cases  not  so, 
the  darkness  sweeping  without  a  break,  like  a  wave,  from,  the  centre 
to  the  circumference. 

The  last-formed  augite  consists  of  very  small  microlitic  crystals, 
their  length  being  from  four  to  ten  times  their  thickness.  They 
are  clear  and  generally  colorless,  but  occasionally  show  a  faint 
greenish  tinge.  It  was  at  times  hard  to  distinguish  them  from 
plagioclase  laths,  and  some  of  the  microlites  which  are  grouped 
under  the  head  of  augite  are  almost  certainly  to  be  referred  to 
apatite,  judging  from  the  amount  of  PaO,  found  in  the  basalt. 
These  microlites  are  thickly  scattered  through  the  basis  of  color- 
less or  brown  glass,  and  give  to  many  of  the  rocks  their  hyalopilitic 
structure. 

Hornblende. — Of  all  the  minerals  composing  the  basalts  of  this 

beck  and  Fennema  (Neue  geol.  Entdeckungen  auf  Java.  N.  J.  II.,  Beil.- 
Bd.,  1883,  p.  21.2),  Petzold  (Basaltgesteine  der  Rbou.  Inaug.  Diss.  Halle, 
1883.  p.  20).  C.  A.  Mttller  (Die  Diabase  aus  dem  liegenden  des  Osttbiiring- 
iscben  Unterdevons.  Inaug.  Diss.  Gera,  1884,  p.  21),  Dannenberg  (Der  Leilen- 
kopf, etc.  Jabrb.  d.  k.  preuss.  geol.  Landanstalt,  1891,  p.  110). 


THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA.         21 

reigon  the  hornblende  offers  the  most  interesting  features  and  is 
the  most  characteristic  and  most  constant  in  its  presence.  Its  con- 
stancy, in  fact,  is  perfect,  it  being  present  as  the  prominent  con- 
stituent in  all  the  Kula  basalts ;  those  of  the  earliest  and  those  of 
the  latest  streams,  those  with  arid  those  without  leucite,  those  with 
much  olivine  and  those  with  little,  in  the  purely  glassy  tachylytes 
as  well  as  in  the  basalts  of  a  normal  structure.  It  is,  in  fact,  the 
stamp  and  seal  of  the  Kula  basalts. 

Megascopically  it  is  much  more  frequent  and  prominent  than 
either  the  augite  or  the  olivine,  and  occurs  as  black  phenocrysts, 
from  2  to  4  mm.  long,  some  few  reaching  a  length  of  6  to  8  mm. 
The  larger  crystals  have  their  surfaces  pitted  and  corroded,  and 
the  crystallographic  planes  present  do  not  admit  of  even  approxi- 
mately exact  measurement.  The  smaller  crystals  and  needles  are 
very  bright  and  fresh-looking. 

Microscopically  it  is  seen  that  the  hornblende  invariably  occurs 
as  porphyritical  crystals,  never  as  a  constituent  of  the  groundmass. 
It  is,  as  a  rule,  well  crystallized,  showing  combinations  of  the  planes, 
c(OOl),  rt(100),  7n(110),  and  r(011),  occasionally  elongated  parallel 
to  6l,  but  usually  in  stout,  thick  crystals.  The  long  prisms  reach 
a  length  of  5-8  mm.,  and  the  short,  stout  crystals  a  length  of  3-4 
mm.,  but  they  commonly  vary  from  1-2  mm.,  and  from  this  run 
gradually  down  to  0.2  mm.  Twins  are  not  common  and  have  the 
usual  twinning  plane,  «(10Q).  Some  intergrown  crystals  may 
represent  other  twinning  laws,  which,  however,  could  not  be.  deter- 
mined. 

The  cleavage  is  very  well  marked,  though  in  some  of  the  more 
glassy  rocks  the  cracks  seem  to  be  less  easily  developed  in  making 
the  slide  than  in  the  less  glassy. 

The  color  is  generally  yellowish  brown,  as  is  the  case  "with 
basaltic  hornblende,  but  some  greenish-yellow  individuals  were 
seen,  often  both  present  in  the  same  slide.  This  green  variety 
shows  a  marked  fondness  for  the  more  glassy  rocks.  Both  varieties 
are  strongly  pleochroic,  the  brown  as  follows  :  c  =  dark  yellowish 
brown,  b  =  yellowish  brown,  a  =  very  pale  fawn-gray,  with  c  >  b 
>  a.  The  green  variety  shows  the  following  pleochroism :  c  = 
dark  brownish  green,  b  light  greenish  brown,  a  pale  fawn-gray,  the 
absorption  being  the  same  as  before.  The  extinction  angle  varies 
from  4°  to  14°  30',  in  one  case  being  as  high  as  23°. 

The  hornblende  crystals  very  commonly  show  a  zonal  arrange- 


22        THE  VOLCANOES   OF   THE   KULA   BASIN   IN   LYDIA. 

.  ment  of  color. ,  This  is  more  frequent  in  the  large  crystals,  the 
small  ones  being  generally  of  one  (light)  color.  It  is  talso  more 
common  in  the  more  glassy  rocks,  though  perhaps  an  explanation 
of  this  is  that  in  the  less  glassy  the  hornblende  has  undergone  pro- 
found alteration,  thus  obscuring  the  original  structure.  These 
zonally  built  crystals  show  a  dark  core,  and,  surrounding  this,  a 
light  border,  both  being  of  the  same  color,  but  of  different  depths 
of  tint,  as  the  zonal  arrangement  is  seen  in  both  the  brown  and  the 
green  varieties.  Occasionally  the  dark  core  is  lighter  towards  the 
centre,  and  very  rarely  the  darker  zone  is  the  outer  one.  Only  in 
a  few  cases  were  four  or  five  alternately  dark  and  light  zones 
observed.  While  instances  occur  where  the  extinction  angle  is  the 
same  in  both  zones,  yet  there  is,  as  a  rule,  a  small  difference,  gen- 
erally from  3°-5°,  in  one  case  as  much  as  9°  40',  the  extinction 
angle  of  the  dark  zone  being  the  greater. 

This  zonal  structure  of  hornblende  has  been  frequently  ob- 
served,* and  appears  to  be  analogous  to  the  zonal  development 
of  the  triclinic  feldspars,  i.e.,  due  to  superposed  growths  of  differ- 
ent minerals  of  the  same  group.  Oebbeke  expresses  the  opinion 
"that  the  border  is  not  monoclinic,  but  triclinic."  (According  to 
the  figure  he  gives,  it  would  seem  that  the  inner  dark  core  is 
meant.)  As  far  as  my  observations  go,  this  seems  not  to  be  the 
case,  at  least  in  the  Kula  basalts,  as  in  sections  parallel  to  a(100) 
both  zones  extinguish  parallel  to  the  single  system  of  cleavage 
lines,  and  in  horizontal  sections  the  direction  of  extinction  in  both 
exactly  bisect  the  angles  of  the  cleavage  rhombus.  One  exception 
must,  however,  be  noted,  where  the  lighter  centre  and  outer  border 
extinguished  parallel  to  the  cleavage  cracks,  in  a  section  parallel  to 
a(100),  while  the  dark  zone  between  has  an  extinction  angle  of 
10°.  30'. 

An  interesting  feature  is  that  the  dark  inner  core  frequently 
shows  a  corroded  outline,  and  then  the  outer  edge  of  the  surround- 
ing light  zone  follows  this  line  very  exactly,  the  small  curves  and 
irregularities  of  the  inner  line  being  often  faithfully  reproduced  in 
the  outer,  the  result  being  a  band  of  equal  width  around  the  dark 
core.  This  proves  that  the  dark  hornblende  was  first  formed  and 

*  Of.  Rosenbusch,  op.  cit.  3te  Auf.  i.  558  ;  Hyland,  Gesteine  des  Kilimand- 
jaro,  Miu.  pet.  Mitth.  x.  243  ;  Oebbeke,  Beitrage  z.  Petrographie  d.  Philip- 
pinen,  etc.,  N.  Jahrb.  Beil.-Bd.  I.  1881,  p.  451  ;  Rudolph,  Petrographie  d. 
Amlen  v.  Peru  u.  Bolivia,  Min.  pet.  Mitth.  ix.  296. 


THE   VOLCANOES    OF   THE    KULA    BASIN    IN    LYDIA.          23 

suffered  corrosion,  and  at  a  later  stage  a  hornblende  containing  less 
iron  was  crystallized  about  this. 

Inclusions  are  not  very  common,  being  chiefly  glass,  either 
colorless  or  clear  brown,  or,  more  frequently,  containing  microlites, 
like  the  glassy  groundmass.  These  glass  inclusions  are  frequently 
arranged  in  a  definite  way,  either  parallel  to  the  crystallographic 
boundaries  of  the  crystal,  or  in  a  similarly-shaped  cluster  or  kernel 
in  the  centre.  One  long  crystal  has  a  line  of  small  brown  glass  in- 
clusions down  the  central  line.  Here  and  there  four  or  six-sided 
sections  are  seen,  which  show  a  large  similarly-shaped  glass  core, 
occupying  nearly  the  whole  of  the  crystal  space,  and  leaving  only 
a  thin  shell  of  hornblende  around  it.  Augite  is  also  a  not  infre- 
quent inclusion  in  hornblende,  this  being  much  more  often  the 
case  than  the  converse.  Magnetite  is  rarely  seen  as  an  inclusion  in 
hornblende,  though  as  an  alteration  product  it  is  very  common,  as 
will  be  seen  later.  In  one  or  two  large  hornblende  crystals  inclu- 
sions of  long  colorless  needles  were  seen,  but  their  optical  proper- 
ties could  not  be  determined,  and  no  cross-sections  were  found. 
They  are  probably  apatite,  being  jnuch  longer  and  larger  than  the 
microlites  of  the  groundmass. 

There  is  no  doubt  that  in  the  Kula  basalts  the  hornblende  is  an 
essential,  original  constituent,  though  in  the  case  of  some  other 
basalts  this  does  not  seem  to  be  quite  so  certain.  Here,  however, 
its  constant  presence — much  more  constant  than  that  of  either  the 
olivine  or  the  plagioclase — its  well  crystallized  form  and  uniform 
method  of  alteration,  and  the  inclusions  of  augite  and  ground- 
mass,  are  all  against  any  other  interpretation  of  its  presence. 

Alteration  of  Hornblende. — The  changes  undergone  by  the  horn- 
blende subsequent  to  its  crystallization  .fall  under  the  three  heads 
of  mechanical  deformation,  simple  corrosion  and  magmatic  altera- 
tion. The  first  two  may  be  passed  over  with  a  few  words,  but  the 
consideration  of  the  latter  will  occupy  more  of  our  space.  It  may 
be  mentioned  that  decomposition  due  to  atmospheric  influences 
was  not  noticed  in  the  hornblende,  and  is  not  here  spoken  of. 

Several  distorted  crystals  were  seen,  and  the  larger  crystals  are 
frequently  broken,  though  this  latter  is  not  as  common  as  is  the 
case  with  the  augite  and  olivine. 

Simple  corrosion,  or  disappearance  of  part  of  the  crystal 
through  magmatic  resorption,  is  quite  common,  deep  bays  and 
pockets  being  often  formed,  which  are  now  filled  with  ground- 


24        THE   VOLCANOES    OF   THE    KULA    BASIN   IN    LYDIA. 

mass.  In  all  these  cases  of  simple  resorption  a  production  of  new- 
formed  substance  has  not  taken  place.  This  form  of  corrosion, 
again,  is  not  as  common  in  the  case  of  the  hornblende  as  with  the 
olivine  or  augite. 

Another  change  which  may  be  ascribed  to  corrosion  is  what  has 
been  called  a  "  melted  appearance  "  of  the  crystal,  when  the  sharp 
edges  are  rounded  and  the  crystal  reduced  to  an  ellipsoidal  or 
approximately  spherical  shape.  This  "  melted  appearance  "  is  al- 
ways accompanied  by  profound  alteration  of  the  crystal,  and  will 
be  spoken  of  later  in  connection  with  the  latter.  The  corrosion  of 
the  inner  dark  core  has  been  already  referred  to. 

We  now  come  to  what  is  perhaps  the  most  interesting  and 
characteristic  feature,  not  only  of  the  hornblende,  but  of  the  basalts 
as  a  whole — the  magmatic  alteration  and  alteration  products  of  the 
hornblende.  These  are  of  three  kinds: 

a.  The   change   of   the   light-colored   hornblende  into  a  dark 
reddish-brown,  almost,. opaque  variety,  without  any  evident  change 
of  form. 

b.  The  formation  of  a  border  or  mass  of  augite  and  opacitic 
grains. 

c.  The  formation  of  a  reddish-brown  mineral,  occurring  in  long 
so-called  "club-shaped"  (keulenformig)  crystals,  accompanied  by 
augite  and  opacite  grains. 

The  first  form  of  alteration  may  be  dismissed  with  a  few  words. 
It  is  seen  almost  exclusively  in  the  scoriaceous  specimens,  and  the 
darkening  takes  place  on  the  outer  parts  of  the  crystal  or  along 
cracks.  There  is  no  change  of  form  or  separation  (ausscheidung) 
of  other  minerals,  and  the  result  seems  to  be  identical  with  that 
observed  by  other  writers,  and  that  produced  by  the  action  of 
molten  magmas  on  hornblende  in  some  experiments.* 

The  second  mode  of  alteration  is  very  frequent  in  all  eruptive 
rocks, f  and  has  been  described  by  many  writers,  J  so  that  it  will 

*  Oebbeke,  loc.  cit.  p.  474;  Lagorio,  Die  Andesite  des  Kaukasus  (Dorpat, 
1878),  p.  25;  Becker,  Ueber  d.  dunkleu  Umraudung  der  Horubleuden,  etc., 
K  Jahrb.  1883,  n.  3;  Belowsky,  loc  cit.  p.  37. 

f  It  is  rare  amoug  the  plutonic  rocks,  but  common  in  Ilie  volcanic  rocks, 
especially  in  tbe  more  basic  of  tbem,  being  frequent  in  the  basalts  and  au- 
desites,  and  almost  unknown  in  tbe  rbyolites. 

JHyland,  Gesteine  d.  Kilimandjaro  (T.  M.  P.  M.,  1888,  x.  240),  gives  an 
almost  complete  list  of  tbe  literature  of  this  and  tbe  following  form  of  altera- 
tion. To  this  may  be  added  tbe  following: 


THE    VOLCANOES    OF   THE    KULA    BASIN    IN    LYDIA.         25 

not  be  described  in  detail  here.  (Cf.  PL  IV,  Fig.  2.)  Suffice  it  to 
.say  that  the  hornblende  becomes  changed  into  a  mass  of  colorless 
Augite  and  black  opaque  grains,  in  many  cases  accompanied  by  a 
rounding  of  the  sharp  edges,  but  in  the  Kula  basalts  generally  with 
the  preservation  of  its  original  form.  The  black  grains,  called  pro- 
visionally opacite,  are  commonly  held  to  be  magnetite,  a  view  with 
which  Becker  does  not  agree.  I  am  inclined  to  think  them — at  least 
the  greater  part — magnetite,  on  account  of  their  exactly  correspond- 
ing appearance  with  the  undoubted  magnetite  of  the  ground  mass 
The  question  is  a  hard  one  to  settle  definitely,  owing  to  the  great 
difficulty  of  separating  these  minute  particles  from  the  containing 
minerals. 

That  most  of  the  colorless  grains  are  augite  *  there  is  no  doubt, 
as  they  offer  the  same  optical  characters  as  the  larger  augite 
crystals  in  the  groundmass,  and  augite  crystals  included  in  the 
hornblende,  showing  the  same  peculiar  blue  and  yellowish  polariza- 
tion colors,  and  being  often — but  not  always — orientated  like  the 
hornblende. 

There  are  also  seen  between  the  augite  and  opacite  grains  some 
particles  of  a  colorless  mineral  the  nature  of  which  is  unde- 
termined. Lenk,  in  the  case  of  some  Khone  basalts,  compares  it  to 
nepheline,  but  shows  that  it  cannot  be  that  mineral.  A  similar  oc- 
currence in  audesitic  hornblende  from  Chapultepec  he  calls  feld- 
.spar,  as  does  C.  Vogelsang  in  hornblende  -  andesite  from  the 

Roseubusch,  Mikr.  Pliys.  11.  passim. 

Streng,  Ueber  d.  Hornblendediabas  v.  Graveneek.  XXII.  Ber.  d.  Oberh. 
•Ges.  f.  Nat.  u.  Heilk.  p.  241. 

Renard,  Notice  s.  1.  Roches  d.  1'isle  de  Kantavu.  Bull.  Acad.  Roy.  d. 
Belg.  (3)  xr.  No.  3. 

Leak,  Geol.  Kenntn.  d.  sildl.  Rhon.  Verlmndl.  d.  phys.-medic.  Gesell.  z. 
Wiirzburg,  N.  F.  xxi,  1887. 

Lenk,  Geol.-petrog.  Miltbeil.  u.  d.  Vulle  de  Mexico.  Habilit  Schrift 
{Leipzig,  1890),  p.  17. 

Reriard,  Petrology  of  Oceau.  Islands  (London,  1889),  129. 

C.  Vogelsang,  Tracbyte  u.  Basalte  d.  Eifel.  Zeit.  d.  d.  geol.  Gesell.  XLII. 
1,  1890.  p.  13. 

Osnnu,  Beitr.  z.  Kenntu.  d.  erupt.  Gest.  d.  Cabo  d.  Gata.  II.  Zeit.  d.  d. 
geol.  Gesell.  XLIII,  1891,  p.  688. 

Osanu,  Basalt  fr.  Southern  Texas.     J.  of  Geol.  i.  344. 

Kiich,  loc.  cit.  p.  55;  Belowsky,  loc.  cit.  p.  44;  Herz  (ditto,,  p.  11G. 
*  Koto  (Studies  of  some  Japanese  Rocks,  Q.  J.  Geol.  Soc.  1884,  p.  439)  was 
the  tirst  to  show  that  these  grains  were  really  augite. 


26      THP:  VOLCANOES  OF  THE  KU.LA  BASIN  IN  LYIHA. 

Kelberg,  in  the  Eifel.  Doss  *  also  observed  it,  but  expressed  no 
opinion  as  to  its  nature.  It  seems  to  me  probable  that  it  is  feld- 
spar, but  I  can  give  no  definite  proof  one  way  or  the  other. 

The  third  effect  of  alteration  may  be  regarded  in  most  cases  as 
a  first  stage  of  a  process  of  which  the  formation  of  an  augite-opacite 
aggregate  is  the  second  and  final  one.  The  characteristic  feature 
of  this  alteration,  which  lias  been  previously  observed  several  times, 
is  the  presence  of  a  reddish-brown  mineral,  occurring  in  long  crys- 
tals, sometimes  thicker  towards  one  end,  whence  the  name  "  keu- 
lenformig  "  (club-shaped)  applied  to  them.  (Cf.  PI.  IV,  Fig.  1.) 
Their  terminations,  while  pointed,  do  not  seem  to  be  strictly  crystal- 
lographic,  and  the  cross-sections  observed  were  irregular  in  outline, 
and  as  far  as  could  be  seen  not  bounded  by  crystallographic  planes. 
In  length  they  vary  from  0.16-0.05  mm.  by  0.03-0.005  mm.  thick. 
Some  appear  to  show  cleavage  parallel  to  the  long  axis. 

In  color  they  are  reddish  brown  to  greenish  brown,  and  are 
strongly  pleochroic  ;  parallel  to  the  long  axis  olive-green,  and  at 
right  angles  to  this  light  brown  and  dark  red-brown  respectively, 
the  last  showing  the  greatest  absorption,  and  the  first  the  least. 
They  are  thus  shown  to  be  biaxial,  as  is  also  indicated  by  the  fact 
that  no  isotropic  sections  were  seen.  The  extinction  appeared,  in 
every  case,  to  be  parallel  to  the  long  axis.  In  many  cases  the  brown 
individuals  are  so  light  in  color,  and  so  sharply  developed  and  sep- 
arate from  each  other,  that  I  had  excellent  opportunities  for  ob- 
servation. This  is  remarked,  inasmuch  as,  in  regard  to  the 
extinction,  my  results  differ  from  those  of  most  other  observers,  as 
will  be  seen  later. 

These  crystals  lie,  not  in  an  irregular  and  confused  way,  but 
the  majority  of  them  arranged  parallel  Jto  the  6  axis  of  the  horn- 
blende crystal,  while  others  cross  these  at  angles  of  about  60°  in 
either  way,  the  measurements  varying  from  57°  to  67°.  These  ob- 
liquely-lying crystals  are  generally  found  along  the  sides  of  the 
hornblende  crystal,  those  in  the  interior  being  mostly  parallel  to 
the  6  axis.  .  In  horizontal  sections  of  hornblende  crystals  most  of 
the  small  crystals  lie  in  planes  parallel  to  the  pinacoids  and  prisms 
of  the  hornblende.  Occasionally  at  the  ends  of  large  hornblende 
crystals,  seen  in  section  parallel  to  6,  the  brown  crystals  are 

*Doss,  Die  bnsaltischen  Laven,  etc.,  der  Hauran,  etc.  Min.  pet.  Mittlu 
vn,  1886,  514. 


THE   VOLCANOES    OF    THE    KULA    BASIN    IN    LYDIA.         27 

grouped  in  tufts,  shaped  like  a  half-opened  fan,  and  spreading 
towards  the  interior  of  the  hornblende.  The  brown  crystals  at 
the  sides  of  the  hornblende  individual  lie  at  angles  of  about  60° 
wsth  the  vertical  edge. 

Filling  the  interstices  between  the  brown  crystals  are  magnetite 
and  colorless  augite  grains,  with  a  few  grains  of  the  undetermined 
mineral  spoken  of  above.  The  brown  aggregate  (which  for  the 
sake  of  convenience  we  shall  call  this  mixture  of  brown  mineral, 
augite  and  magnetite)  is  formed  along  the  outer  surfaces  of  the 
original  hornblende,  and  also  on  the  sides  of  cracks,  and  on  some 
broken  or  corroded  surfaces.  In  a  few  cases  large  fragments  of 
hornblende  crystals  show  this  alteration  on  the  original  planes, 
while  the  fracture  edge  runs  across  both  the  fresh  and  the  altered 
substance.  It  seems  to  show  a  preference  for  the  brown  variety  of 
hornblende,  and  especially  for  the  dark  form  of  this.  In  many 
cases  the  inner  dark  core  is  altered  to  brown  aggregate,  while  the 
outer  light  zone  is  unchanged,  showing  that  the  dark  hornblende 
was  first  altered  and  the  lighter  colored  hornblende  subsequently 
deposited  on  the  surface. 

It  is  to  be  remarked  that  this  alteration  to  brown  aggregate  has 
taken  place  in  nearly  every  case  without  marked  change  of  the 
original  form  or  surfaces  of  the  hornblende  crystal,  though  in  some 
cases  the  altered  hornblende  has  undergone  corrosion,  like  the  un- 
altered, but  not  to  as  great  aii  extent. 

It  has  been  already  stated  that  the  two  last-described  alterations 
are  apparently  separate  stages  of  one  process,  and  the  following 
facts  may  be  adduced  in  favor  of  this  view.  The  hornblende 
crystals  which  have  been  altered  to  brown  aggregate  near  the  outer 
surface  or  along  cracks  have  the  rest  of  their  substance  perfectly 
unaltered.  (PL  IV,  Fig.  1.)  Sometimes  the  alteration  has  pro- 
ceeded so  far  that  only  a  small  kernel  of  the  original  hornblende  is 
left,  and  again  none  remains,  the  whole  of  the  hornblende  being 
altered.  Very  often  an  augite-opacite  border  is  seen  around  the 
brown  aggregate,  though  it  also  happens,  but  more  rarely,  that  the 
augite-opacite  border  is  present  without  the  brown  aggregate.  In 
the  former  case  the  hornblende  crystal  is  made  up  of  a  kernel  of 
unaltered  hornblende,  around  this  a  zone  of  brown  aggregate,  and 
again  outside  this  a  ring  of  augite-opacite  aggregate,  with  gener- 
ally the  line  of  demarcation  between  the  last  two  very  ill-defined. 
This  may  be  called  the  second  stage,  the  third  being  where  all  the 


28        THE   VOLCANOES    OF   THE   KULA   BASIN    IN   LYDIA. 

hornblende  substance  has  disappeared,  giving  place  to  a  core  of 
brown  aggregate  and  an  outer  zone  of  augite-opacite.  The  last 
stage  is  where  the  brown  aggregate  has  entirely  disappeared  and 
there  remains  of  the  hornblende  nothing  but  a  so-called  "  pseudo- 
crystal  "  of  augite-opacite  aggregate,  with  or  without  change  of 
form.  (PI.  IV,  Fig.  2.) 

These  last  two  stages  are  beautifully  shown  in  the  second- 
period  basalts,  especially  in  that  from  a  well-digging  in  the  town  of 
Kula,  to  be  spoken  of  later.  It  must,  however,  be  remarked  that 
an  alteration  to  brown  aggregate  seems  to  be  not  necessary  to  the 
formation  of  the  augite-opacite  aggregate,  but  that  the  hornblende 
itself  is  readily  changed  into  the  latter  without  the  preliminary 
formation  of  brown  aggregate.  This  observation  agrees  with  those 
of  other  observers,  and  an  explanation  of  it  is  given  on  a  following 
page. 

The  most  striking  fact  in  connection  with  these  two  alterations 
is  the  perfect  manner  in  which  the  original  hornblende  crystal 
has  as  a  rule  preserved  its  form,  notwithstanding  the  great 
chemical  changes  it  has  undergone.  Taking  into  consideration 
the  fact  that  the  new  product  is  granular  and  not  compact,  the 
outlines  are  wonderfully  sharp,  allowing  of  quite  exact  measure- 
ments of  the  angles  presented  by  the  sections.  Doelter  and 
Hussak  *  mention  the  same  fact  in  regard  to  hornblende  which 
was  subjected  to  the  action  of  a  molten  basaltic  magma  in  two 
of  their  experiments,  and  several  instances  of  the  same  phenom- 
enon in  nature  will  be  found  in  the  literature  on  the  subject. 

There  are,  however,  exceptions,  chiefly  in  the  last  stage,  and  in 
the  second-period  basalt.  Here,  as  already  mentioned,  the  altered 
hornblende  crystals  are  rounded  and  present  an  appearance  which, 
Sommerlad  f  graphically  says,  looks  as  if  they  had  melted  and  run, 
or,  as  Hylaud  puts  it,  looks  as  if  they  had  been  "washed."  These 
rounded  forms  chiefly  occur  in  the  case  of  the  smaller  crystals, 
and  almost  always  when  they  have  been  completely  altered  to  an 
augite-opacite  aggregate.  Some  cases  were  seen  where  the  brown 
aggregate  has  evidently  been  disintegrated  and  scattered  through 
the  substance  of  the  rock.  In  two  cases  a  large  augite  (one  with 

*  Doelter  and  Hussak,  Ueber  die  Eiuwirkung  geschmolzener  Magmeu  auf 
verschiedene  Mineralien.  K  Jahrb.  1884,  i.  p.  24. 

f  Sommerlad,  jj.Ueber  bornblendefilhrende  Basaltgesteiue.  N.  Jahrb.  II. 
Beil.-Bd.  1886,  141. 


THE   VOLCANOES    OF   THE   KULA   BASIN   IN   LYDIA.         29 

an  accompanying  olivine  crystal)  had  surrounding  part  of  it  (and 
of  the  olivine)  a  "  mantle  "  or  fluid  ally  arranged  covering  of  brown 
aggregate,  and  in  other  cases  particles  of  brown  aggregate  are 
scattered  as  inclusions  through  large  clear  augite  crystals.  In  one 
or  two  instances  inclusions  of  well-shaped  hornblende  crystals 
altered  to  brown  aggregate  were  seen  in  augite  crystals.  All  these 
cases  are  exceptional,  but  taken  together  seem  to  show  that  the 
augite  was  formed  at  about  the  same  time  that  the  alteration  of  the 
hornblende  was  taking  place,  in  the  first  cases  the  augite  having 
evidently  been  formed  before  or  at  the  same  time,  and  in  the 
others  subsequently.  It  must  be  also  noted  that  no  instance 
was  seen  of  an  augite  inclosing  hornblende  altered  to  augite-opacite. 

The  Kula  basalts  are  all  very  glassy,  yet  it  was  observed  to  be 
the  rule  that  the  more  glassy  the  rock  the  less  the  alteration,  the 
last  stages  being  reached  only  in  the  least  glassy  varieties.  This 
fact  has  also  been  observed  by  many  writers,  including  Rosenbusch, 
Hyland,  Lenk,  Petzold,  and  Kiich. 

To  return  to  the  brown  aggregate  stage  of  alteration,  there  is 
given  in  a  note  *  the  literature  on  the  subject  so  far  as  the  writer's 
knowledge  of  it  extends.  From  an  examination  of  this  it  will 
seen  that,  first  observed  by  Zirkel  in  1870  in  the  basalt  of  the 
Niirburg  in  the  Eifel,  it  has  subsequently  been  found  in  basalts  of 

*  Zirkel,  Basal  tgesteine,  p.  26. 

Rosenbusch,  Mik.  Phys.  8te  Aufl.  i.  560. 

M5bl,  Die  Basalte  u.  Phonolithe  Sachsens(1873),  p.  130. 

Van  Werveke,  Beitr.  z.  Kenntn.  d.  Gesteine  d.  Insel  Palma.  Neues 
Jahrb.  1879,  p.  825. 

Backing,  Jahrb.  d.  geol.  Landesanstalt,  1880,  p.  160. 

Sommerlad,  Ueber  hornblendeftihrende  Basalte.  Neues  Jahrb.  1882,  n. 
Beil.-Bd.  p.  150. 

Petzold,  Basaltgesteine  der  RhOn.     Inaug.  Diss.     Halle,  1888.     p.  26. 

Doss,  Die  basaltische  Laven  und  Tuffe  der  Haurfin.  Min.  pet.  Mitth.  vn, 
1886,  p.  515. 

Lenk,  Zur  geol.  Kenntn.  der  sudl.-RhOn  (Wurzburg,  1887),  p.  79. 

Hyland,  Ueber  die  Gesteine  des  Kilimaudjaro.  Min.  petr.  Mitth.  x,  1888. 
p.  238. 

Hatch,  On  the  Characters  of  Rocks  collected  in  Madagascar.  Q.  J.  Geol. 
Soc.  1889,  p.  349. 

C.  Vogelsang,  Trachyte  und  Basalte  der  Elfel.  Zeit.  d.  deutsch  geoL 
Gesell.  XLII,  1890,  p.  19. 

Osann,  Beitr.  z.  Kenntn.  der.  Gesteine  des  Cabo  da  Gata.  II.    Ditto, 
1891,  p.  688. 

Zirkel,  Lehrbuch  d.  Petrographie,  1893,  i,  719. 


30        THE   VOLCANOES   OF  THE   KULA    BASIN   IN    LYDIA. 

Saxony,  Palma,  the  Khone,  the  Hauran  in  Syria,  Kilimandjaro, 
Madagascar,  and  Gabo.de  Grata.  All  these  hornblende  .basalts 
seem  to  have  been  poor  in  glass,  and  most  of  them  to  have  con- 
tained nepheline,  as  is  usually  the  case  in  hornblende  basalts, 
though  in  the  present  instance  none  was  found.  The  descriptions 
of  the  brown  mineral  agree  perfectly,  except  in  one  point,  with 
my  own  observations.  Through  the  kindness  of  Prof.  Dr.  Zirkel 
and  Dr.  Lenk,  I  was  also  able  to  examine  slides  of  the  basalts 
from  the  Eifel,  and  the  Spahler  Berg  and  Sparbrod  on  the  Ehon, 
and  establish  the  identity  of  these  occurrences  with  my  own. 
The  exception  spoken  of  is  the  oblique  extinction  which  almost  all 
the  writers  observed,  varying  from  "  parallel  or  little  inclined  " 
(van  Werveke)  to  maxima  of  20°  (Hyland)  and  25°  (Doss),  the 
usual  extinction  angle  lying  between  7°  and  15°.  It  is  to  be 
noted  that  Doss  (p.  515)  observed  in  one  or  two  specimens  from 
the  Tell  Sfech  that  the  altered  hornblende  contained  not  only 
small,  dark-brown,  club-shaped  "  hornblende "  crystals,  but  also 
small  "  rod-like,"  yellowish-red  to  yellow  crystals  which  have  par- 
allel extinction  and  whose  chemical  nature  is  undetermined. 
Similar  contradictory  statements  are  made  in  regard  to  the  be- 
havior of  the  brown  crystals  towards  hydrochloric  acid,  some  of 
the  authors  stating  that  they  are,  others  that  they  are  not,  acted  on 
by  it. 

The  general  opinion  is  that  these  "club-shaped"  bodies  are 
also  hornblende,  though  Petzold,  Hyland,  and  Lenk  are  inclined  to 
doubt  this,  and  leave  the  question  an  open  one.  The  smallness  of 
the  crystals,  their  intimate  mixture  with  the  other  alteration  prod- 
ucts, and  the  consequent  difficulty,  nay,  impossibility,  of  complete 
separation,  render  a  chemical  analysis  of  the  pure  material  out  of 
the  question,  and  their  nature  must,  to  a  large  extent,  at  least  as 
far  as  the  occurrences  observed  up  to  the  present  time  are  con- 
cerned, be  determined  on  other  grounds  than  chemical  ones. 

All  the  non-chemical  means  of  investigation  seem  to  me  to 
point  to  the  conclusion  that  these  small  reddish-brown  crystals  are 
in  reality  hypersthene,  and  the  reasons  for  this  opinion  are  now 
given.  It  must  be  premised  that  I  do  not  regard  the  point  as 
proved  and  the  question  definitely  settled,  the  arguments  I  am  pro- 
ceeding to  bring  up  going  to  show  the  great  probability  of  the 
mineral  being  hypersthene,  and  not  amounting  to  positive  proof. 
The  result  of  an  unsatisfactory  chemical  analysis  will.be  given 
later. 


THE   VOLCANOES   OF  THE    KULA    BASIN   IN   LBYIA.         31 

a.  In  the  first  place,  the  investigations  of  a  number  of  ob- 
servers *  on  melted  hornblende  show  that  on  cooling  (at  least  under 
the  laboratory  conditions  chosen)  it  cecrystallizes  as  augite.  This 
is  the  unanimous  result  of  all  their  experiments,  and  no  case  is 
known  where  hornblende  recrystallized  as  hornblende.  As  Hyland 
pertinently  says,  "  One  cannot  well  explain  theoretically  how  this 
tendency  of  melted  hornblende  to  crystallize  out  as  augite  can  be 
overcome."  The  results  of  the  above-cited  experiments  seem*  to  me 
also  a  strong  ground  for  doubting  the  hornblende  nature  of  the 
body  in  question,  and  for  supposing  it,  on  a  priori  grounds,  to  be- 
long  to  the  pyroxene  group. 

b.  The  pleochroism  of  the  crystals  agrees  perfectly  with  that  of 
hyperstheue,  which  is  givenf  as  o  or  a  brownish  red,  b  or  b  reddish 
yellow,  c  or  b  green.     Hyperstheue  is  usually  elongated  or  prismatic 
parallel  to  6,  and  taking  the  long  axis  of  our  crystals  as  6,  we  find 
an  absolutely  identical  pleochroism.     Some  of  the  crystals  also  show 
a  tendency  to  become  tabular  parallel  to  J(010),  judging  from  the 
pleochroism,  which  is  quite  frequent  in  hypersthene,  but  not  the 
usual  habit. 

c.  The  constant  parallel  extinction  observed  by  me  (cf.  Van 
Werveke,  Doss,  and  Osann)  points  to  a  rhombic  mineral,  taken  in 
connection  with  the  pleochroism,  and  strengthens  the  idea  that  we 
have  to  do  with  hypersthene. 

In  contradistinction  to  my  observations  stands  the  almost  unani- 
mous testimony  of  the  various  observers  that  the  mineral  extin- 
guishes obliquely.  That  this  is  a  serious  objection  to  the  hypersthene 
theory  I  must  admit;  yet  it  can,  I  think,  be  explained  in  two  ways. 
It  must  be  remembered  that  in  almost  all  the  cases  quoted  the  crys- 

*  Mitscherlich  and  Berthier,  Pogg.  Ann.  1831,  xxn.  338. 

G.  Rose,  ibid. 

Fouque  and  Michel-Levy,  Synth^se  des  Mineraux  et  des-  Roches  (Paris, 
1882),  pp.  61-78. 

Becker,  Dunkle  Umraudungen  der  Horublenden.    Neu.  Jahrb.  1883,  n.  8. 

Doelter  and  Hussak,  Einwirkuug  geschuiolzeuer  Magmeu.  Ibid.  1884, 
i.  24. 

Becker.  Schmelzversuche  mit  Pyroxnen  und  Ampuibolen,  Zeit  d.  d. 
geol.  Ges.  xxxvii.  1885,  p.  10. 

Cf.  Ramnjelsberg,  Mineralchemie .  u.  394. 

t  Dana,  Mineral.  6th  ed.  1892,  p.  349.  Cf.  Blaas,  Jilngere  Eruptivges- 
tei'ne  Persians  (Min.  pet.  Mitth.,  in.,  1880,  p.  482),  and  Hatch,  Gesteiue  d. 
Vulcan  Gruppe  von  Areqiiipa  (ibid.,  VH,  1886,  339). 


32        THE    VOLCANOES   OF  THE   KULA    BASIN   IN    LY1HA. 

tals  are  spoken  of  as  being  "very  dark/'  or  "almost  opaque."  and 
"  only  allowing  of  optical  examination  in  thin  parts  of  the  slide." 
I  conclude  from  this  that  the  slides  were  relatively  thick,  especially 
in  the  case  of  the  earlier  investigators,  and  so  the  oblique  extinction 
might  have  been  caused  by  augite  grains,  unaltered  hornblende,  or 
particles  of  feldspar,  lying  above  or  below  the  brown  mineral.  It 
also  seems  possible  that,  unconsciously,  a  personal  bias  may  have- 
entered  into  the  question;  i.e.,  that  the  observers  had  the  idea  that 
the  mineral  was  hornblende,  and  thought  they  saw  an  oblique  ex- 
tinction when  it  was  in  reality  parallel.  The  illusion  would  have 
been  heightened  by  the  form  of  the  crystals,  which  are  often  thicker 
at  one  end  than  at  the  other.  However  this  may  be,  I  can  only  say 
that,  in  my  slides  of  the  Kula  basalts,  the  mineral  was,  in  most  cases, 
light  colored,  large,  and  well  formed  enough  to  admit  of  exact  opti- 
cal examination;  that  only  such  crystals  were  relied  on;  that  they 
all  extinguished  parallel;  and  that  this  parallel  extinction  was  ob- 
served and  noted  while  I  still  thought  the  mineral  hornblende,  and 
before  the  idea  of  its  be'ing  hypersthene  had  occurred  to  rne. 

d.  It  will  be  remembered  that  in  sections  parallel  to  b  of  the  horn- 
blende most  of  the  crystals  are  arranged  parallel  to  this,  with  others 
crossing  them  at  angles  of  60°,  while  in  sections  perpendicular  to 
the  vertical  axis  the  crystals  are  mostly  perpendicular  to  the  pina- 
coids  and  prisms  of  the  hornblende.  On  the  supposition  that  these 
crystals  are  hornblende  in  the  latter  case  the  arrangement  can  be  ex- 
plained as  analogous  to  the  network  of  rutile  needles  crossing  at  angles 
of  60°  in  mica;  but  for  the  other  case  no  such  explanation,  based 
on  the  crystallographic  properties  of  the  host,  can  be  given,  the 
only  important  angles  in  hornblende  near  60°  or  120°  being  that  of 
the  prismatic  cleavage,  which  would  only  affect  the  needles  seen  in 
horizontal  section.  The  only  twinning  planes  so  far  known  in 
hornblende  are  a(WO)  and  c(OOi),  the  latter  giving  rise  to  twin- 
ning lamellae.  Therefore,  as  we  cannot  find  the  explanation  in  tho 
original  hornblende  crystal,  we  must  look  for  it  in  the  mineral  itself; 
and  here  the  hypersthene  theory  comes  readily  to  our  aid,  and  fur- 
nishes us  with  a  good  explanation.  We  find,  in  fact,  that  the  dome 
(101)  is  a  twinning  plane  of  hypersthene,  giving  an  angle  between 
the  two  6  axes  of  60°  58',  it  being  also  a  twinning  plane  of  the  allied 
mineral  enstatite.  Becke*  observed  in  andesite  from  southern 


*  Becke,  Ueber  Zwillingsverwachsungen  Gesteinbildender  Pyroxeneu  und 
Ampbibolen.     Min.  Pet.  Mitth,,  vn.  p.  93. 


THE   VOLCANOES   OF   THE   KULA   BASIN   IN   LYDIA.        33 

Bukowina  hypersthene  needles  twinned  in  accordance  witli  this 
law,  producing  stellate  forms,  and  he  compares  them  with  angite 
twins  with  the  twinning  plane  W(122). 

e.  It  has  long  been  known  that  augite  and  hornblende  tend  to  crys- 
tallize (when  together)  in  parallel  position — that  is,  with  the  6  axes 
and  the  ortho-  and  cliuo-pinacoids  parallel.  Hypersthene  has  been 
o.bserved*  as  an  inclusion  in  augite  in  parallel  position,  and  hence 
it  can  be  inferred  that  it  would  also  lie  in  parallel  position  in  horn- 
blende. This  has,  in  fact,  been  observed  by  Hatch  and  Osann  in 
cases  cited  below,  and  by  Lacroix.  If  now  we  consider  our  mineral 
hypersthene,  we  find,  by  means  of  the  pleochroism,  that  the  crystals 
lying  with  their  long  axes  parallel  to  the  hornblende  6  have  mostly 
their  macro-pinacoids  parallel  to  the  brachy-pinacoids  of  the  horn- 
blende, as  is  also  the  case  in  the  parallelism  of  pyroxene  and  horn- 
blende. 

/.  The  alteration  of  hornblende  into  hypersthene  (along  with 
other  minerals)  has  been  already  several  times  recorded. f  Hatch 
describes  occurrences  in  andesites  from  the  volcano  Pichupichu  near 
Arequipa,  where  the  hornblende  has  become  altered  to  a  mass  of 
feldspar,  augite,  hypersthene,  and  magnetite  grains  and  crystals, 
the  augite  and  hypersthene  being  in  parallel  position.  Rudolph's 
and  Lenk's  examples  are  not  as  striking,  while  Osann  refers  the 
rhombic  pyroxene  observed  by  him  to  bronzite.  It  must  be  re- 
marked that  in  all  these  cases  of  rhombic  pyroxene  as  an  alteration 
product  of  hornblende,  it  was  also  present  in  the  rock  proper.  " 

(f.  On  general  chemical  and  mineralogical  grounds  it  seems 
unlikely  that,  after  the  alteration  of  part  of  the  hornblende  to 
augite  and  magnetite,  the  rest  of  it  should  again  crystallize  as  horn- 
blende. 

The  above  are  my  arguments  in  favor  of  the  hypersthene  hypothe- 
sis. As  previously  remarked,  they  are  not  held  to  be  entirely  con- 
clusive, but  as  indicating  a  great  probability.  The  subject  seems  a 
difficult  one,  but  the  difficulties  have  so  far  been  chiefly  those 
offered  by  the  unsatisfactory  nature  of  the  occurrences.  With 


*  Bucca,  Le  Andesite  dell'  Isola  di  Lipnri.  Boll.  R.  Com.  Geol.  d'ltalia, 
Nos.  9  and  10,  1885,  p.  286.  Lacroix.  Sur  Quelques  Roches  d'Armenie.  Bull. 
Soc.  Geol.,  3d,  xiv.,  1891,  p.  744. 

f  Rudolph,  op.  cit.  p.  294  ;  Hatch,  Arequipa,  pp.  352,  354  ;  Lenk,  Mexico, 
p.  17  ;  Osann,  op.  cit.  p.  688. 


34        THE    VOLCANOES   OF   TIIF    KTTLA    BASIN   IN   LYDIA. 

better  material,  which  I  hope  to  obtain,  the  question  can  undoubt- 
edly be  definitively  settled. 

In  one  of  the  hand  specimens  from  the  well-digging  before  referred 
to  was  found  a  dark  spot,  some  two  or  three  centimetres  in  diame- 
ter. On  examination  under  the  microscope  this  proved  to  be  a 
mass  of  brown  aggregate,  magnetite,  and  some  large  augite  crystals, 
with  very  little  unaltered  hornblende.  It  was  thought  that  the 
brown  crystals  could  perhaps  be  separated,  and  material  enough 
obtained  for  chemical  analysis,  so  the  dark  spot  was  reduced  to  a 
coarse  powder,  and  the  groundmass  separated  by  means  of  Thou- 
let's  solution.  It  was  impossible  thus  to  separate  the  brown  mineral 
from  the  augite,  and  the  brown  mineral,  as  well  as  the  magnetite, 
was  attracted  by  the  magnet.  An  attempt  was  therefore  made  to 
separate  the  magnetite  by  digestion  with  warm  dilute  HC1.  Con- 
siderable iron  was  extracted,  but  it  is  to  be  feared  that  some  of 
the  brown  mineral  was  itself  decomposed,  and  hence  the  analytical 
results  partially  vitiated.  However,  an  analysis  of  the  resulting 
material  was  made  with  the  following  result,  the  alkalies  not  hav- 
ing been  determined: 

H80(Ign.) 0.50 

SiO, 49.00 

Ala03 - 7.78 

Fe20s 7.62 

FeO 2. 93 

CaO 19.60 

MgO 10.44 

KaO,Na,0 _ 

97.87 

This  result,  it  will  be  seen,  is  against  the  theory  of  hypersthene 
being  present  in  any  considerable  quantity.  For,  hypersthene  being 
a  ferrous  magnesium  meta-silicate  with  a  percentage  of  FeO,  vary- 
ing from  10.04  to  28.40  %*  we  would  expect  in  the  material 
analyzed  not  only  a  much  larger  percentage  of  FeO  than  was  found, 
but  also  that  the  quantity  of  FeO  present  would  be  greater  than 
that  of  the  Fe203.  The  very  large  percentage  of  CaO  is  striking, 
and  seems  only  explicable  on  the  theory  that  a  much  larger  quantity 

*  Dana,  op.  ell.  p.  350.   ' 


THE    VOLCANOES  OF  THE   KULA   BASIN   IN   LYDIA.         35 

of  augite  was  present  than  the  microscopical  examination  seemed  to 
show. 

It  is  remarkable  that  this  analysis  is  almost  identical  with  analy- 
sis of  augites  from  Kircheip  and  Naurod,  and  shows  much  resem- 
blance to  those  of  augites  from  the  Vogelsberg  and  Greenwood 
Furnace.*  I  am  inclined  to  say  that  much  of  the  iron  was  lost 
through  the  treatment  with  HC1,  though  I  must  admit  that  this 
would  not  necessarily  alter  the  relative  proportions  of  ferrous  and 
ferric  iron,  unless  the  ferrous  iron  present  is  more  easily  dissolved. 
It  is  much  to  be  deplored  that  the  result  obtained  is  so  unsatis- 
factory, but  I  hope  on  my  next  visit  to  Kula  to  obtain  more 
appropriate  material. 

Theories  of  Alteration. — We  are  next  confronted  with  the  prob- 
lem of  the  formation  of  this  brown  aggregate,  and  the  augite- 
opacite  aggregate,  which  has  engaged  the  attention  of  many 
investigators,  but  which  seems  to  be  still  in  an  unsettled  and 
unsatisfactory  condition.  While  agreeing  with  Hyland  and  Som- 
merlad  as  to  the  difficulty  of  the  explanation,  I  think  it  worth 
while  to  examine  the  question  and  to  offer  my  quotum  toward  its 
solution. 

It  must  be  remembered  that  we  have  two  processes  to  consider, 
or,  what  is  perhaps  more  correct,  two  stages  of  one  process.  It  is 
true  that  in  most  cases  of  similar  alteration  of  hornblende  and 
biotite  the  formation  of  brown  aggregate  has  not  been  observed 
(never  in  the  case  of  biotite);  but  the  evident  close  connection  of 
the  two  methods  of  alteration  in  the  rocks  under  discussion  makes 
it  seem  probable  that  they  are,  at  least  partially,  due  to  the  same 
cause  or  causes.  It  is  possible  that  one  of  the  causes  to  be  brought 
forward  later  may  explain  the  difference  in  the  two,  but  they  will 
at  present  be  discusse^  together. 

It  may  be  well  to  state  first,  in  compact  form,  the  various  phe- 
nomena which  must  be  explained  by  any  theory  proposed.  The 
brown  hornblende  seems  much  more  subject  to  these  alterations 
than  the  green.  The  hornblende  is  generally,  but  not  necessarily, 
changed  first  to  a  brown  aggregate,  and  next  to  an  augite-opacite 
aggregate;  in  the  process  some  of  the  Fea03  being  reduced  to  FeO. 
This  change  takes  place  first  near  the  surface  of  the  crystal  and 
works  inward,  or  else,  especially  in  the  case  of  the  brown  aggregate, 

*  Daua,  op.  tit.  p.  360,  Nos.  71,  72. 


36        THE  VOLCANOES   OF  THE   KULA    BASIN   IN   LYDIA. 

along  cracks,  and  here  without  contact  with  the  surrounding  rock 
magma.  The  alteration,  especially  that  to  brown  aggregate,  often 
occurs  without  any  change  of  form  in  the  hornblende  crystal.  A 
layer  of  unaltered  hornblende  substance  can  be  deposited  on  horn- 
blende altered  to  brown  aggregate,  but  it  was  not  observed  around 
the  augite-opacite.  The  augite-opacite  alteration  is  seldom,  and 
the  other  never,  met  with  in  the  plutonic  or  more  acid  volcanic 
rocks,  and  both  alterations  seem  to  be  more  common  the  less  glassy 
the  groundmass.  The  brown  aggregate  seems  to  have  been  formed 
at  a  comparatively  early  period. 

We  shall  first  state  the  various  theories  and  ideas  that  have  been 
advanced  on  the  subject,  as  by  a  general  view  and  comparison  we 
can  more  readily  determine  what  is  of  value  and  what  may  be  re- 
jected. It  must  be  stated  that  the  theories  attributing  this  altera- 
tion to  atmospheric  action  and  decomposition,  and  the  views  that 
the  magnetite,  etc.,  are  inclusions,  are  not  considered,  as  numerous 
facts  observed  since  their  proposal  have  effectually  disposed  of 
them. 

Zirkel,*as  the  cause  of  the  formation  of  the  augite-opacite  border,. 
says  "that  the  dark  opacite  border  is  the  product  of  the  caustic- 
chemical  action  of  the  surrounding,  still  half-molten  magma  on  the 
already  crystallized  hornblende  crystals." 

Kosenbusch,  describing  the  so-called  pseudomorphs  of  mag- 
netite after  hornblende  and  biotite,  says  I :  "  Such  pseudomorphs 
appear  to  be  conditional  on  resorption  of  the  older  porphyritical 
crystals,  which,  in  certain  stages  of  development  of  the  magma,  are 
not  able  to  exist."  In  describing  the  dark  border  of  biotite  J  he  re- 
marks that  it  is  less  developed  the  more  glassy  the  groundmass, 
"  since  here  the  solidification  was  completed  before  conditions 
could  enter  which  would  endanger  the  existence  of  the  biotite." 
In  another  place  §  he  attributes  the  alteration  to  the  action  of  the 
magma  during  the  eruption,  there  being  at  this  period  a  great 
change  in  the  chemical  constitution  of  the  magma,  "  and  loss  of 
water  through  sudden,  or  at  least  rapid,  diminution  of  pressure,  and 
the  consequent  considerable  increase  of  its  acidity." 

*  Zirkel,  Ueber  die  krystalliuischen  Gesteiue  langs  des  40te   Breitgrades 
in  Nordwest-Amerika.     Ber.  d.  k.  Sachs.  Ges.  d.  Wiss.  1877.  p.  197. 
f  Rosenbusch,  op.  cit.  8te  Aufl.  i.  p.  285. 
i  Ditto,  i.  p.  583. 
§  Ditto,  2te  Auti.  ir.  p.  660. 


THE   VOLCANOES    OF  THE   KULA    BASIN  IN   LYDIA.         37 

Sommerlad,*  after  remarking  that  an  explanation  seems  hard 
to  find,  goes  on  as  follows:  "  Perhaps  the  original  crystals  were  here 
melted,  either  only  on  the  borders,  or  else  completely,  and  the 
microlites  were  produced  during  quick  cooling,  and  at  the  same  time 
particles  of  the  groundmass  penetrated  between  them." 

Petzold  f  speaks  thus:  "  Perhaps  one  can  form  the  following 
conception  of  their  genesis  [of  the  brown  crystals] :  The  early  crys- 
tallized hornblende  underwent  the  solvent  action  of  the  molten 
magma,  out  of  the  solution  there  separated  later  augites,  together 
with  feldspar  and  the  brown,  hornblende-like  mineral.  From  a 
chemical  point  of  view  there  is  nothing  against  this  theory." 

Siemiradzki  J  thinks  that  "  hornblende  is  produced  in  the  depths 
in  circumstances  of  strong  saturation  of  the  magma  by  superheated 
steam,  and  great  pressure,  while  augite  separates  at  the  surface  on 
cooling  of  the  dry  magma.  The  opacitic  border  of  the  hornblende 
crystals  arises  through  action  of  the  dry  (freed  from  the  crystal- 
forming  H.,0  vapor)  molten  magma  on  the  crystals  floating  in  it, 
while  the  augite  is  unacted  on." 

Lagorio  §  says :  "  The  cause  of  the  corroding  action  of  the 
molten  mass  on  the  already  crystallized  ingredients  is  to  be  looked 
for,  primarily,  in  the  changed  chemical  composition,  which  the  still 
fluid  part  undergoes  through  separation  of  successive  generations 
of  ingredients.  But  this  change  is  not  yet,  it  appears,  enough  for 
an  effective  assault  on  the  already  formed  minerals.  There  is 
necessary  for  this  still  another  circumstance."  This  other  circum- 
stance he  takes  to  be  the  heat  developed  through  diminution  of 
volume  on  solidification,  and  he  goes  on  :  "This  explains  suffi- 
ciently well  the  frequent  occurrence  of  opaque  borders,  and  other 
corrosion  appearances  in  crystals  in  rocks,  in  which,  after  separa- 
tion of  the  primary  ingredients,  further  crystallization  took  place." 

Kiich,  I  after  stating  Zirkel's,  Rosenbusch's,  and  Lagorio's  views 
on  the  subject,  admits  that  a  corrosive  action  of  the  magma  has 
undoubtedly  taken  place  where  the  original  contours  of  the  horn- 

*  Sommerlad,  op.  cit.  p.  150. 

f  Petzold,  op.  cit.  p.  29. 

|  Siemiradzki,  Geologiscbe  Reiseiiotizen  aus  Ecuador.  N.  Jahrb.  Beil.-Bd. 
iv,  1886,  207. 

§  Lagorio,  Ueber  die  Natur  der  Glasbasis.  Miu.  pet.  Mittb.  vui,  1887, 
462. 

||  Kiicb,  op.  cit.  pp.  56.  57. 


38        THE   VOLCANOES    OF  THE   KULA   BASIN   IN    LYDIA. 

blende  are  more  or  less  changed.  He  contends,  however,  that  in 
the  case  of  hornblende  crystals  which  have  preserved  their  original 
forms,  and  also  where  a  separation  of  magnetite  grains  has  taken 
place  in  the  interior  of  the  crystal,  that  no  such  corrosive  action  is 
possible.  His  explanation  is  that  the  alteration  is  due  to  a  "  simple 
action  of  heat." 

Belowsky,*  while  admitting  that  Kiich's  theory  explains  many 
appearances,  yet  does  not  admit  that  it  will  explain  all.  "  Accord- 
ing to  my  opinion,  the  solvent  and  decomposing  activity  of  the 
molten  magma  is  to  be  put  in  the  first  rank." 

It  is  seen  on  examination  of  these  various  theories  that  all  the 
writers  quoted,  with  the  exceptions  of  Sommerlad,  Petzold,  Kuchr 
and  Belowsky,  follow  Zirkel  in  attributing  the  alteration  to  a  cor- 
rosive action  of  the  molten  magma,  differing  in  details,  and  in  their 
explanations  of  the  action.  Exactly  what  sort  of  action  this  is  sup- 
posed to  be  is  not  clear,  though  most  seem  to  imagine  a  chemical 
reaction  of  some  sort  between  the  magma  and  the  hornblende. 
Rosenbusch  and  Lagorio  introduce  certain  physical  conditions  a& 
necessary — the  one  diminution  of  pressure,  the  other  a  sudden  rise 
in  the  temperature  on  solidification,  the  latter  being  also  invoked 
by  Sommerlad  to  account  for  the  melting  of  the  hornblende  after 
solidification.  Petzold  and  Belowsky  both  suppose  a  solution  of 
the  hornblende  crystal  by,  and  subsequent  deposition  of  augite  and 
opacite  from,  the  molten  magma.  Kiich,  on  the  other  hand,  at- 
tributes the  change  entirely  to  the  simple  influence  of  heat,  without 
fusion  of  the  crystal. 

Zirkel's  explanation  that  the  action  of  the  molten  magma  i& 
one  of  a  "  caustic-chemical "  nature  may  stand  as  the  general  state- 
ment of  this  class  of  explanations,  though  the  phrase  is  rather  a 
vague  one,  and  with  no  very  definite  meaning. 

Lagorio  rightly  objects  to  Rosenbusch's  theory  that  it  is  not  clear 
what "  Umstande  "  are  meant,  but  that  probably  the  quicker  cooling 
in  glassy  rocks  is  thought  of.  He  disproves  this  by  an  experiment 
of  plunging  a  biotjte  crystal  into  a  molten  acid  and  alkali-rich  magma, 
and  then  allowing  the  mass  to  cool.  The  solid  mass  is  perfectly 
glassy,  but  the  biotite  crystal  shows  in  the  section  an  opacitic  bor- 
der, though  the  action  of  the  molten  magma  was-almost  momentary. 
The  high  percentage  of  SiO,  (in  this  case  ca.  69$)  would  seem  to 

*  Belowsky,  op.  cit.  p.  45. 


THE    VOLCANOES    OF  THE   KULA    BASIN   IN   LYDIA.        39 

favor  Roseubusch's  idea  that  the  acidity  of  the  basis  has  to  do 
with  the  corrosion.  Against  this  it  may  be  urged  that  the  Kula 
basalts  are  basic  rocks  with  a  percentage  of  silica  of  47.5-48.  We 
learn  from  some  analyses  of  basalt  and  their  glass  bases  by 
Lagorio*  that  the  difference  in  acidity  of  a  basic  rock,  poor  in 
alkalies,  and  its  glass  basis  is  practically  nothing,  in  two  cases  the 
glass  being  even  slightly  more  basic  than  the  basalt.  It  is  there- 
fore safe  to  assume  that  the  glass  basis  of  the  Kula  basalts — and 
hence  the  molten  magma  at  all  stages — was  a  basic  one,  and  yet  we 
have  here  the  alteration  extremely  well  marked  and  very  constant. 
An  objection  to  Sommerlad's  theory  is  that  one  would  expect,  in 
accordance  with  his  idea  of  quick  cooling,  to  find  the  brown  crys- 
tals, and  augite  and  opacite  grains,  as  frequently  in  the  very  glassy 
rocks  as  in  the  less  glassy,  which  we  know  net  to  be  the  case.  Pet- 
zold  remarks  that  this  theory  is  forced,  and  justly  says  that  if  this 
were  the  case  one  would  expect  to  find  the  microlites,  and  so  forth, 
in  the  neighborhood  of  such  altered  hornblende  crystals,  which  we 
do  not.  This  objection  would  also  lie  against  Petzold's  theory 
itself,  against  which  perhaps  no  chemical  objection  can  be  brought, 
but  grave  physical  ones.  But  it  seems  to  me  that  the  strongest 
argument  against  these  or  similar  theories  involving  a  fusion  or 
solution  of  the  hornblende  crystal  is  the  fact  that  so  many  cases 
occur  where  the  hornblende  is  altered  in  substance  and  yet  not  in 
form.  One  cannot  say  that  in  the  one  case  the  alteration  in  sub- 
stance is  due  to  one  cause  and  in  the  other  case  to  another,  as  Kiich 
seems  to  do,  since  the  alteration  product  in  both  is  identical,  but  we 
can  logically  attribute  the  alteration  of  substance  and  alteration  of 
form  to  different  causes.  To  me  it  is  impossible  to  conceive  of  any 
body  preserving  its  sharp  outlines  if  existing  in  a  fluid  or  semi-fluid 
state  in  a  moving  molten  magma;  and  that  the  magma  was  in  mo- 
tion after  (and  hence  during)  the  alteration  is  shown  by  the  fluctu- 
ation structure  of  the  microlites  about  all  the  larger  altered  crys- 
tals. That  after  the  solidification  of  the  surrounding  magma  the 
hornblende  could  have  become  fused  without  losing  its  form  ispos- 
ble,  but  that  such  should  happen  before  solidification  of  the  magma 
I  hold  is  impossible.  Belowsky  exclaims,  "  Why  should  not  the 
sharp  contours  of  the  crystals  be  retained  on  a  solution  of  the 
hornblende  and  immediate  separation  of  augite- and  ore-grains  ?" 

*  Lagorio,  op.  cit.  p.  479. 


40        THE   VOLCANOES   OF  THE   KULA    BASIN    IN    LYIHA. 

But  it  seems  to  me  much  more  proper  to  ask,  Why  should  they  be 
retained  ?  Such  an  occurrence  would  run  counter  to  all  our  experi- 
ence. The  idea  also  of  immediate  separation  of  augite  and  mag- 
netite which  he  has  to  suppose,  and  which  Sommerlad  is  also  com- 
pelled to  bring  in,  seems  decidedly  forced,  unnatural,  and  unneces- 
sary. So  I  shall  exclude  from  consideration  as  an  explanation  of 
the  alteration  of  substance  any  fusion  or  solution  of  the  crystal,  as 
being  not  in  accordance  with  the  observed  facts.  The  change  of 
form  often  seen,  in  some  cases  very  profound  and  amounting  to  a 
complete  scattering  of  the  altered  crystal  through  the  rock  sub- 
stance, is  not  necessarily  due  to  fusion,  but  is  much  more  probably 
simple  mechanical  disintegration,  the  granular  pseudomorph  not 
being  as  coherent  as  the  unaltered  crystal. 

Siemiradzki's  view  that  the  hornblende  was  formed  at  a  consid- 
erable depth  under  conditions  of  great  pressure  and  saturation  of 
the  magma  with  superheated  steam  seems  to  me  to  have  much 
to  recommend  it.  It  js  chiefly  based  on  the  fact  that  so  far  we  have 
been  unable  to  produce  hornblende  under  conditions  of  dry  igne- 
ous fusion,  while  augite  is  readily  so  produced.*  I  cannot,  how- 
ever, agree  with  him  in  regard  to  the  period  of  formation  of  the 
augite.  In  the  Kula  basalts  the  augite  is  frequently  an  inclusion  — 
often  in  large  crystals — in  the  hornblende,  this  being  much  more 
often  the  case  than  the  converse.  Indeed  part  of  the  augite 
seems  to  have  been  formed  at  the  same  time  as,  if  not  before,  the 
hornblende,  and  the  formation  of  the  two  apparently  went  on  hand- 
in-hand  for  some  time,  the  formation  of  hornblende  finally  ceasing, 
while  that  of  the  augite  as  rnicrolites  still  continued.  It  is  per- 
fectly possible  that  augite  may  be  formed  in  a  moist  molten  magma 
as  well  as  in  a  dry  one.  His  explanation  of  the  cause  of  the  altera- 
tion is  a  general  one  and,  with  the  exception  of  the  magma  being 
supposed  dry,  apparently  identical  with  Zirkel's.  An  objection  to 
his  theory  that  the  alteration  is  dependent  on  the  dryness  of  the 
magma  lies  in  the  fact  that  steam  is  usually  present  in  the  lava 
when  it  reaches  the  surface,  and  hence  the  magma  is  hardly  ever  in 
his  supposed  waterless  condition.  This  objection,  however,  lies 
only  against  his  explanation  of  the  alteration,  not  of  the  formation, 
of  the  hornblende,  his  view  of  the  latter  seeming  to  me  to  be  a  very 
probable  one. 

*Cf.  Fouque  et  Levy,  Syuthese  cles  Miueruux  et  des  Roches,  p.  102. 


THE   VOLCANOES   OF  THE   KULA    BASIN   IN   LYDIA.         41 

That  Lagorio's  "  changed  chemical  constitution  of  the  magma  " 
due  to  loss  of  some  of  the  constituents  as  minerals  crystallized  out 
is  not  always  a  necessary  condition,  seems  to  be  shown  by  the  fact 
that  zones  of  unaltered  hornblende  are  seen  around  altered  sub- 
stance. The  rise  in  temperature  due  to  solidification — which  has 
in  fact  been  observed  * — may  enter  as  a  factor,  and  will  be  spoken  of 
again. 

To  sum  up:  Though  the  process  under  discussion  is  strictly  a 
chemical,  or  physico-chemical,  alteration,  yet,  as  crystallization  of 
the  newly  formed  bodies  takes  place,  it  may,  I  think,  be  justly 
assumed  that  factors  of  simple  crystallization  would  also  play  a  role 
in  the  present  process. 

Michel-Levyf  gives  the  three  factors  of  temperature,  pressure, 
and  mineralizing  agents,  as  bringing  about  crystallization  in  molten 
magmas.  He  further  remarks  that  in  basic  rocks  pressure  and 
mineralizing  agents  are  of  little  importance,  and  the  minerals  we 
can  ascribe  to  them — biotite  and  basaltic  hornblende — are  rare  in 
basic  magmas,  and  in  the  last  phases  of  rock  formation  are  often 
absorbed  and  changed  to  augite  and  magnetite. 

Iddings  J  in  an  able  paper  gives  the  following  list,  the  factors 
being  arranged  in  the  order  of  their  importance  : 
"  Cooling,  and  a  certain  amount  of 
Time,  or  the  Rate  of  Cooling. 
Chemical  Composition  of  the  magma. 
Mineralizing  Agents. 
Pressure." 

Some,  or  all,  of  these  may  enter   into  the   problem,  and  I  would 
further  propose  two  additional  ones. 

But  we  must  now  take  up  for  consideration  the  two  modes  of 
alteration  separately,  as  the  conditions  of  the  formation  of  the  two 
aggregates  produced  are  evidently  not  quite  the  same.  We  will  first 
consider  the  brown  aggregate,  as  this  is  the  first  formed,  and,  to  a 
certain  extent,  leads  to  the  other. 

*"Scacchi,  Palmieri,  and  Guariui  observed  this  phenomenon  during  the 
eruption  of  Vesuvius  in  1855  in  the  lava  of  the  Fossa  della  Vetrana.  Cf.  Roth, 
Der  Vesuv  und  die  Umgegeud  von  Neapel.  Berlin,  1857,  pp.  293  and  304." 
Note  in  Somuierlad,  op.  cit.  p.  142. 

f  Michel-Levy,  Structure  et  Classification  des  Roches  eruptives.  Paris, 
1889.  pp.  5  and  9. 

t  Iddiugs,  On  the  Crystallization  of  Igneous  Rocks.  Bull.  Phil.  Soc. 
Washington,  xi.  1889,  pp.  106,  113. 


42        THE   VOLCANOES   OF   THE    KULA    BASIN   IN   LYDIA. 

For  the  formation  of  this  (the  brown  aggregate)  I  would  intro- 
duce a  factor,  the  effect  of  which  seems,  heretofore,  to  have  been  un- 
recognized, namely,  the  chemical  action  of  gas  occluded,  or  otherwise 
present,  in  the  molten  magma.  Hydrogen  is,  of  all  gases,  the  most 
easily  occluded  by  a  molten  magma,  and  that  it  is  abundant  in  the 
gases  given  off  during  eruptions  is  well  known.  Its  presence  is  un- 
doubtedly due  to  the  dissociation  of  water  at  the  high  temperature- 
of  the  fluid  lava.  If  we  adopt  Siemiradzki's  theory  we  must  sup- 
pose that  the  crystallization  of  the  hornblende  started  at' a  consider- 
able depth,  when  the  lava  was  saturated  with  water  vapor,  due 
to  the  ingress  of  water  which  started  the  eruption.  As  the  lava  as- 
cends the  conduit  this  water  vapor  becomes  partially  dissociated,  the- 
dissociation  of  steam  taking  place  gradually,  as  shown  by  experi- 
ments. Whether  Siemiradzki's  theory  is  correct  or  not,  hornblende 
is  present  (as  shown  by  the  broken  and  distorted  crystals)  in  the- 
moving  mass  of  magma  containing  occluded  hydrogen  at  a  high 
temperature.  This  hydrogen,  occluded  and  hence  in  close  molecu- 
lar contact  with  the  ingredients  of  the  mass,  would  exert  a  power- 
ful reducing  action  on  the  hornblende  (which  seems  especially  sub- 
ject to  certain  forms  of  alteration),  reducing  the  Fe303  to  FeO, 
with  the  production  of  hypersthene,  magnetite,  and  some  augite. 
The  hydrogen,  it  will  be  observed,  could  penetrate  crevices  that  the 
molten  magma  would  be  unable  to  do,  and  so  account  lor  the  fre- 
quent alteration  we  observe  in  such  places.  That  this  action  should 
take  place  only  in  basaltic  rocks  seems  at  first,  perhaps,  an  objec- 
tion. But  when  we  remember  that  it  is  almost  solely  in  these  rocks 
that  brown  hornblende  occurs,  that  this  variety  is  the  only  one  that 
contains  Fea08  to  a  large  extent,  and  that  in  the  Kula  basalts,  as 
well  as  in  other  instances,  this  is  the  only  variety  altered,  the  green 
generally  remaining  unchanged,  we  have,  I  think,  found  the  ex- 
planation. It  is  only  in  these  rocks  that  the  hornblende  contains 
iron  in  a  reducible  condition.  It  would  seem  from  this  that  it  re- 
quires the  reduction  of  Fea03  to  FeO,  and  not  merely  the  presence 
of  FeO,  for  the  formation  of  the  brown  (hypersthene)  aggregate. 
In  this  alteration  it  would  seem  that  the  chemical  constitution  of 
the  magma  may  be  left  out  of  account  as  a  direct  factor,  it  having, 
of  course,  to  do  in  the  first  place  with  the  formation  of  a  brown 
hornblende  rather  than  a  green.  However  this  may  be,  it  is  cer- 
tain that  a  high  temperature  is  necessary,  not  only  for  the  dissoci- 
ation of  the  water,  but  for  the  reducing  action  of  the  resultant 


THE  VOLCANOES   OF   THE   KULA   BASIN   IN   LYDIA.         43 

hydrogen.  That  pressure  is  necessary  seems  probable,  but  of  this 
we  cannot  be  certain.  It  will  have  been  noticed  that  for  all  this 
process  no  fusion  or  solution  of  the  hornblende  is  necessary,  and 
hence  the  crystal  may  retain  its  shape  and  sharp  edges,  as  we  find  to 
be  the  case.  As  the  dissociation  of  water  begins  at  a  temperature 
considerably  above  that  of  the  melting-point  of  basalt,  at  a  higher 
point  of  the  conduit  much  of  the  dissociated  hydrogen  and  oxygen 
would  recombine,  producing  a  moist  magma,  and  hence,  through 
the  absence  of  free  hydrogen,  preventing  further  alteration,  and  al- 
lowing the  production  of  fresh  hornblende,  which  would  either  be 
deposited  on  the  already  altered  crystals,  or  else  separate  out  as 
smaller  crystals. 

The  formation  of  an  augite  opacite  aggregate  is  a  different,  and 
perhaps  a  simpler,  process.  It  must  be  borne  in  mind  that,  as 
shown  previously,  it  invariably  takes  place  at  a  later  stage  than  the 
alteration  into  brown  aggregate. 

Of  Iddings'  list  of  factors  given  above  we  can  safely  eliminate 
those  of  pressure  and  mineralizing  agents,  on  the  ground  of  La- 
gorio's,  Becker's,  and  Doelter  and  Hussak's  experiments,  which 
show  that  hornblende  can  be  altered  to  an  augite-opacite  aggregate 
under  ordinary  atmospheric  pressure,  and  in  a  dry  magma,  without 
the  presence  of  mineralizing  agents.  In  this  I  am  at  one  with 
MichelrLev3%  though,  as  will  have  been  gathered  from  foregoing 
remarks,  I  cannot  admit  the  resorption  of  hornblende,  in  this  case. 

It  would  perhaps  seem  reasonable  to  exclude  also  the  chemical 
constitution  of  the  magma,  since  we  find  the  same  alteration  tak- 
ing place  in  acid  and  basic,  and  alkali-rich  and  alkali-poor,  magmas. 
Against  this  can  be  urged  the  undoubted  fact  that  the  alteration  is 
more  frequent  in  the  basic  vulcanic  rocks.  Perhaps  an  explanation 
similar  to  that  brought  forward  for  the  same  factor  in  the  brown- 
aggregate  formation  could  be  found,  but  at  present  it  seems  best  to 
retain  this  factor,  though  with  some  hesitation. 

That  a  high  temperature  is  necessary  is  certain,  but  that  the  rate 
of  cooling  enters  in  is  rather  doubtful,  since  arguments  can  be 
brought  forward  on  both  sides.  However,  on  the  ground,  chiefly, 
of  the  more  frequent  occurrence  in  the  less  glassy  rocks,  it  must  I 
think  be  retained,  though,  like  the  preceding,  with  some  hesitation. 

Into  this  process  I  would  also  introduce  a  new  factor,  a  molec- 
ular change  similar  to  that  occurring  in  many  bodies  under  certain 
conditions,  as  the  change  of  monoclinic  to  orthorhombic  sulphur, 


44        THE  VOLCANOES   OF  THE   KULA   BASIN   IN    LYDIA. 

and  that  of  many  organic  compounds  into  isomers  or  polymers.  I 
suggest  then  that  this  alteration  is  due  to  a  chemical  action  of  the 
magma — the  nature  of  which  is  not  very  clear — on  the  hornblende 
crystal,  either  unaltered  or  changed  to  brown  aggregate,  in  the  lat- 
ter case  the  brown  mineral  (hypersthehe)  alone  being  affected. 
This  obscure  chemical  action  is  aided,  or  perhaps  superseded,  by  a 
molecular  change  going  on  in  the  crystal  itself  due  to  a  long-con- 
tinued high,  but  gradually  diminishing,  temperature,  or  a  slow  rate 
of  cooling.  This  molecular  change  splits  up  the  hornblende  mole- 
cule, the  ferrous  and  ferric  oxides  present  going  chiefly  to  form 
magnetite  and  the  CaO  and  MgO  forming  (with  a  small  pro- 
portion of  the  iron)  a  colorless  pyroxene,  which  is  probably  a 
diopside.  It  seems  probable  that  the  composition  of  amphibole  is 
a  more  complicated  one  than  that  of  pyroxene,  and  "  Tschermak* 
has  shown  reason  for  writing  the  amphibole  formulas  as  double  the 
corresponding  ones  for  pyroxene."  It  is  also  to  be  seen  that  the 
formula  of  an  aluminous  hornblende  containing  Fe203  is  more 
complicated  than  that'of  a  (probably)  non-aluminous  pyroxene  con- 
taining little  or  no  iron.  Hence  the  molecule  is  much  more  readily 
split  up,  and  subject  to  alteration  under  conditions  which  would 
not  affect  the  augite  molecule.  The  same  reasoning  applies  in  the 
case  of  the  brown  aggregate  alteration. 

The  above  explanation  of  what  is,  it  must  be  confessed,  a  diffi- 
cult subject  is  roughly  given,  and  may  not  be  completely  satisfac- 
tory. Still  it  seems  to  me  to  be  fully  as  reasonable  as,  and  more 
definite  than,  any  of  the  theories  heretofore  proposed,  and  gives  an 
explanation  for  all  the  observed  phenomena.  My  time  and  space 
do  not  permit  me  to  go  into  the  details  of  this  last  point,  or  to  enter 
into  a  longer  discussion  of  the  subject,  but  enough  has,  I  think, 
been  said  to  make  the  theory  clear,  and  the  reader  can  follow  out 
its  application  at  his  leisure. 

Olivine. — One  of  the  characteristic  features  of  the  Kula  basalts 
is  the  relatively  small  quantity  of  olivine  present,  which,  while  very 
constant  in  its  occurrence,  forms  but  a  very  small  proportion  of  the 
component  minerals.  It  is  always,  like  the  hornblende,  porphy- 
ritic.  The  largest  oli vines  vary  from  0.5-3.0  mm.  and  are  nearly 
all  fragmentary.  The  smaller. crystals  vary  from  0.05-0.4  mm.  in 
length  by  nearly  the  same  in  thickness,  and  are,  in  contradistinc- 

*  Tschermak,  Miii.  pet.  Mittb.  xxxvin,  1871.     Cf .  Dana,  Miner,  p.  388. 


THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA.         45 

tion  to  the  larger,  usually  well  formed.  They  show  the  planes 
fl(100),  5(010),  wi(110),  rf(101),  and  £(021).  Frequent  rect- 
angular sections  are  seen,  indicating  the  absence  of  prisms  or 
domes  on  many  of  the  crystals.  Though  the  largest  oli vines  are 
bright  greenish  yellow  as  seen  macroscopically,  in  sections  they  are 
both  colorless  and  are  remarkable  for  their  perfect  clearness  and 
freedom  from  alteration.  With  the  exception  of  two  specimens 
from  A'i  Tepesi,  where  the  olivine  is  colored  a  clear  reddish  yellow 
on  the  border,  the  olivine  is  without  a  trace  of  decomposition  of 
any  sort.  This  freshness  of  appearance  and  the  colorlessuess,  taken 
together  with  the  imperfect  way  in  which  the  augite  shows  its  cleav- 
age, rendered  it  a  matter  of  great  difficulty  at  times  to  distinguish 
the  two  minerals. 

Though  the  smaller  olivines  are,  as  a  rule,  well  formed,  yet  here 
and  there  peculiar  forms  due  to  irregularities  of  growth  and  devel- 
opment, to  which  olivine  is  very  prone,  were  seen,  in  some  cases  the 
angles  being  developed  more  than  the  faces.  What  is  probably  due 
to  a  similar  cause  is  shown  in  PL  III.,  Fig.  5,  though  it  may  be  a 
corrosion  phenomenon.  There  we  have  a  section  parallel  to  a(100), 
showing  the  brachypinacoid  6(010)  and  the  dome  £(021).  It  is  seen 
that  the  angles  are  sharp,  while  piercing  all  the  domes  are  holes 
leading  to  shallow  cavities  filled  with  groundmass.  The  bottoms  of 
these  cavities  are  not  flat  but  convex,  and  their  comparatively  great 
width  and  narrow  mouth  are  very  striking.  A  crystal  similar  to 
these  is  seen  in  the  sideromelan  nucleus  of  a  manganese  nodule 
from  the  bed  of  the  South  Pacific.*  Another  inclusion  form 
which  seems  to  be  a  consequence  of  growth  is  shown  in  Fig.  6. 
Here  two  large  spots  of  clear  brown  glass  are  seen  at  each  end  of  an 
olivine  crystal.  This  arrangement,  which  is  quite  often  met  with, 
is  probably  due  to  the  formation  of  a  crystal  forked  at  the  two 
ends,  as  is  so  common  in  olivine,  the  filling  of  the  open  spaces 
with  groundmass — at  that  period  apparently  free  from  microlites 
or  magnetite — and  the  subsequent  growth  of  olivine  substance  be- 
yond and  around  them,  completing  the  crystal  form,  and  isolating 
the  two  masses  of  glass.  In  another  case  (Fig.  7)  a  hexagonal  sec- 
tion is  seen  with  four  bands  of  brown  glass  lying  parallel  to  the 
prisms,  and  in  still  another  we  have  a  lozenge-shaped  section  of 


*  Report   of  the  Voyage    of  H.M.S.  "Challenger":  Deep-sea  Deposits. 
London,  1891.    PI.  XVI.,  Fig.  1. 


46        THE   VOLCANOES   OF  THE   KULA   BASIN    IN    LYDIA. 

oliviue,  about  this  a  zone  of  ground  mass,  and  about  this  again  a 
shell  of  olivine  of  the  same  shape  as  the  core  (Fig.  8).  Inclusions 
are,  however,  not  very  common  and  are  mostly  of  brown  glass  or 
groundmass,  each  crystal  containing  but  one  or  two.  They  are  oc- 
casionally relatively  large,  and  are  also  sometimes  of  the  same  shape 
as  the  host. 

Besides  these  glassy  inclusions  there  were  seen  two  olivine  crys 
tals  containing  peculiar  trichite  inclusions,  such  inclusions  being,  it 
may  be  stated,  of  rare  occurrence  in  basaltic  hornblende.  The  first 
is  in  a  hyalopilitic  basalt  from  one  of  the  knolls,  and  is  shown  in 
Fig.  9.  Here  there  are  two  olivine  crystals,  one  1.2  X  0.4  mm.  and 
of  rectangular  outline,  and  another  of  about  the  same  size,  but 
broken,  adjoining  it.  In  these  are  seen  very  fine,  hair-like  black 
lines,  which  by  the  aid  of  high  powers  are  resolved  into  rows  of 
extremely  minute  black  grains,  sometimes  looking  as  if  strung 
along  a  fine  black  hair.  In  the  larger  crystal  these  margarites  do 
not  lie  irregularly,  but' the  majority  of  them  are  perfectly  straight 
and  parallel  to  the  long  sides  of  the  crystal,  often  curving  about  at 
the  ends  so  as  to  enclose  an  oblong  space.  In  the  broken  crystal 
they  are  mostly  curved,  and  do  not  lie  as  regularly,  but  still  are 
generally  in  groups  of  individuals  parallel  to  one  another.  At  the 
junction  of  the  two  crystals  is  a  narrow  black  border  on  each,  from 
which  many  small  trichites  emanate. 

The  second  case,  occurring  in  the  upper  scoriaceous  part  of  a 
" knoll,"  is  of  an  olivine  crystal,  0.55x0.45  mm.,  shown  in  Fig.  10. 
It  is  of  an  ovoidal  shape,  with  flat  ends,  and  is  sharply  divided  into 
two  parts  along  a  line  running  across  it  at  its  widest  part.  The 
larger  half  shows  a  colorless  mass  of  olivine,  containing  numerous 
coarse  black  lines,  which  can  be  readily  resolved  into  rows  of  black 
grains.  These  margarites  are  all  curved  and  lie  in  groups  of  mem- 
bers parallel  to  one  another.  The  smaller  half  looks  under  low 
powers  almost  perfectly  black  and  opaque,  but  the  higher  powers 
show  it  to  be  also  made  up  of  colorless  olivine  substance,  with 
numerous  black  grains  and  trichites,  mostly  arranged  in  parallel 
straight  and  curved  lines. 

Both  these  occurrences  resemble  the  trichite  inclusions  in  the 
olivine  of  a  gabbro  from  Mull  described  and  figured  by  Zirkei.* 

*  Zirkei,  Mikroskopische  Beschaffenkeit  de  Mineraliern  (Leipzig,  1873),  p. 
214.  Cf.  Renard,  Petrol.  Oceau.  Islands  (London,  1889),  p.  57. 


THE    VOLCANOES   OF  THE   KULA    BASIN   IN   LYDIA.        47 

The  olivine  also  frequently  shows  signs  of  corrosion,  which  has 
generally  acted  irregularly,  forming  deep  bays  and  pockets.  In 
many  cases  the  original  outline  has  been  entirely  lost  and  only  a 
small  part  of  the  original  crystal  is  left.  It  also  happens  that  one 
end  of  a  crystal  will  be  perfectly  unacted  on  and  show  sharp  angles 
and  straight  lines,  while  the  other  end  will  be  deeply  eaten  away. 
All  these  appearances  are  so  common  and  have  been  so  often  de- 
scribed and  figured  that  it  was  not  thought  worth  while  to  illus- 
trate them. 

One  special  case,  which  may  however  be  due  to  growth,  is  here 
shown  (Fig.  11).  It  is  a  rectangular  section,  0.2  X  0.14  mm.,  from 
one  angle  of  which  runs  a  small  prolongation  of  the  side.  This 
extinguishes  exactly  like  the  body  of  the  crystal  and  is  not  an  ad- 
hering fragment. 

Magnetite. — This  occurs  both  in  the  groundmass  and,  as  already 
described,  as  an  alteration  product  of  hornblende.  In  size  the 
grains  vary  from  0.005-0.03  mm.,  a  few  attaining  a  diameter  of  0.1 
mm.  when  the  sub-metallic  lustre  in  reflected  light  is  easily  seen. 
These  large  grains  are  irregular  in  shape,  but  the  smaller  ones  fre- 
quently show  sharp  outlines,  representing  sections  of  octahedra. 

A  very  interesting  observation  was  made  in  regard  to  its  occur- 
rence in  the  groundmass,  which  has  an  important  bearing  on  the 
•question  of  its  period  of  formation.  It  will  be  remembered  that 
the  Kula  basalts  can  be  divided  as  regards  their  structure  into 
normal,  hyalopilitic,  semi-vitreous,  and  tachylytic  varieties,  and  it 
may  be  further  stated  that  all  these  varieties  possess  practically  the 
.same  chemical  composition. 

In  the  first  two  types — the  least  glassy — the  magnetite  is  very 
abundant  and  the  glass  basis  colorless.  In  the  semi-vitreous  variety 
the  magnetite  is  only  sparingly  present  and  the  glass  basis  a  light 
cinnamon-brown.  In  the  tachylytes — which  are  almost  pure  glass — 
the  magnetite  is  almost  entirely  absent  and  the  glass  a  dark  choco- 
late-brown. 

Here  we  have  a  beautifully  shown  transition  series,  the  magnet- 
ite content  varying  inversely  as  the  glass  content  and  as  the  depth 
of  color  of  the  glass  basis.  This  seems  very  good  proof  that  the 
magnetite  is,  in  these  basalts,  not  one  of  the  first  minerals  to  crys- 
tallize out  as  is  generally  held  to  be  the  case,*  but  that  it  was  among, 

*  Cf.  Roseubuscli,  op.  cit.  3te  Aufl.  i.  287.,  n.  342.     It  is  interesting  to  note 


48        THE   VOLCANOES   OF   THE   KULA    BASIN   IN    LYDIA. 

if  not  quite,  the  last.  The  facts  that  magnetite  is  very  rarely  seen 
as  an  inclusion  in  the  other  minerals,*  and  the  numerous  inclu- 
sions of  clear  brown  glass,  point  the  same  way. 

It  may  be  objected  that  an  explanation  of  this  lack  of  magnetite 
in  the  more  glassy  basalts  is  to  be  found  in  a  reabsorption  by  the 
magma.  This,  however,  seems  forced  and  impossible,  it  being  diffi- 
cult to  explain  a  reabsorption  in  the  quickly  cooled-rocks,  Avhile 
such  an  action  did  not  take  place  in  the  slowly-cooled  ones.  It  has 
also  been  pointed  out  by  Iddingsf  that  the  first  mineral  to  separate 
out  is  the  last  to  be  reabsorbed,  and  vice  versa.. 

The  above  observations  are  quite  contrary  to  the  generally  held 
views  on  the  subject  of  the  relative  age  of  the  magnetite  in  a  given 
rock,  but  there  can  be  no  doubt  of  the  facts  stated.  They  form 
one  of  the  prominent  characteristics  of  the  whole  series  of  slides, 
and  hardly  an  exception  was  to  be  found  to  the  general  rule.  It 
may  be  mentioned  that  Vogt  has  shown  in  a  recent  workj  that  in 
the  case  of  some  slags  the  magnetite  is  crystallized  out  after  the 
olivine. 

Leucite. — This  mineral  was  observed  only  in  the  lava  of  the 
northeast  and  southeast  streams,  and  in  only  one  specimen  of 
lapilli  from  the  crater  of  Kula  Devlit  out  of  half  a  dozen  exam- 
ined. The  crystals  are  all  small,  from  0.05-0.3  mm.  in  diameter, 
perfectly  colorless,  and  only  occasionally  show  anomalous  double 
refraction.  The  outlines  are  generally  rounded,  but  here  and  there 
some  distinct  octagonal  sections  are  seen.  They  contain,  as  usual, 
microlitic  inclusions  of  augite  and  magnetite,  the  former  being 
much  the  more  common.  These  augite  microlites  are  generally 
arranged  in  one  or  two  rings,  concentric  with  the  outline  of  the 
crystal,  while  the  magnetite  is  more  irregular.  A  few  are  seen 
with  a  nucleus  of  dusty  opaque  grains  occupying  the  centre  of 
the  crystal,  and  an  augite-microlite  ring  surrounding  this.  These 
resemble  the  leucites  in  a  leucite-basanite  from  Kilimandjaro 
described  by  Hyland.§ 

that  Judd  (Scot.  Gabbros,  Q.  J.  Geol.  Soc.  1886,  79)  observed  exactly  the  op- 
posite state  of  affairs  in  the  basalts  of  western  Scotland.  • 

*  The  magnetite  which  occurs  as  an  alteration  product  of  hornblende  is,  of 
course,  not  referred  to  in  this  connection. 

f  Iddings,  Crystal.  Ign.  Rocks,  loc.  cit.  p.  105. 

t  Vogt,  Mineralbildung  in  Schmelzmassen  (Kristiania,  1892),  p.  210. 

§  Hyland,  op.  cit.  p.  261. 


THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA.         49 

The  occurrence  of  leucite  in  connection  with  hornblende  basalts 
is  interesting,  the  combination  never  before  having  been  observed. 
It  may  be  also  mentioned  that  this  is  only  the  second  recorded 
occurrence  of  leucite  in  Asia  Minor,  La  Croix*  having  observed  it 
in  rocks  brought  from  Trebizonde,  and  which  he  identified  as 
leucite  tephrites  and  leucitites.  These  leucite  rocks  seem  to  have 
their  eastern  continuation  in  Persia,  f 

Apatite. — This  was  only  seen  once  or  twice  in  the  second-period 
basalt  from  a  well-digging  in  Kula.  In  this  rock  hexagonal  sec- 
tions were  observed,  about  0.1  mm.  in  diameter,  pale  gray  in  color, 
and  with  lines  of  very  fine  dust-like  grains  crossing  each  other 
at  angles  of  GO0.  These  few  crystals,  however,  are  not  integral 
parts  of  the  rock,  but  are  undoubtedly  derived  from  enclosures  of 
foreign  rock  brought  up  from  below.  One  such  enclosure  of 
plagioclase  containing  many  identical  apatites  was  seen  in  the  same 
slide. 

The  rather  large  percentage  of  P20B ,  in  one  case  0.97$,  equiva- 
lent to  about  2.5$  of  apatite,  is  to  be  explained  on  the  supposition 
that  some  of  the  microlites  present  in  the  groundmass  are  in 
reality  apatite.  Many  of  them  do  extinguish  parallel  to  the  long 
axis,  but  also  many  obliquely.  The  latter  may  be  considered 
augite,  and  part  of  the  former  apatite. 

Melanite  and  Spinel — Only  three  crystals  of  the  former  were 
found  ;  one,  0.01  mm.  in  diameter,  in  the  groundmass  of  a  hyalo- 
pilitic  "  knoll "  basalt,  and  two  smaller  crystals  as  inclusions  in  a 
large  augite,  in  a  specimen  from  the  northeast  stream.  They  are 
all  dark  brown  in  color,  with  high  relief.  All  three  are  almost 
undoubtedly  derived  from  inclusions  which  have  been  altered  by 
contact  with  the  basalt,  and  do  not  form  essential  ingredients  of 
the  rock.  A  few  crystals  of  green  spinel  were  seen  in  the  ground- 
mass,  but  they  are  so  evidently  derived  from  enclosures  of  foreign 
rock  that  further  remarks  on  them  will  be  deferred  to  a  later  page. 

Biotite. — Two  crystals  of  dark-brown  biotite  were  seen,  both 
undoubtedly  derived  from  foreign  rock.  One,  in  a  glassy  knoll 
basalt,  is  a  brown  crystal  fresh  in  the  interior  but  altered  in  the 
outer  part  to  a  border  of  augite  and  opacite  grains,  and  a  brown 

*  Lacroix,  Sur  les  Roches  a  Leucite  de  Trebizonde.  Bull.  Soc.  Geol.  de 
France,  xix.  1891,  p.  732. 

t  Steinecke,  Leucitbasalte  u.  a.  Leucitgesteine  in  Peisien.  Z.  f.  Naturwiss. 
Halle,  4,  vi,  1887,  p.  1. 


50        THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA. 

minenil  which  looks  extremely  like  the  brown  mineral  found  in 
the  hornblende.  The  crystals  are  similar  in  shape,  but  the  pleoch- 
roism  is  not  as  well  marked  here,  and  the  two  colors  observed  were 
dark  brown  parallel  to  the  long  axis  and  light  brown  at  right 
angles  to  this.  The  extinction  was  parallel.  I  think  it  probable 
that  these  crystals  are  the  same  mineral  as  in  the  hornblende,  and 
if  so  it  will  be  the  first  case  in  which  it  has  been  found  in  biotite. 
The  second  biotite  crystal  was  in  the  lava  of  Kara  Tepe,  dark 
brown,  and  showed  no  signs  of  alteration.  Here  the  rock  was 
more  glassy  than  in  the  other  case. 


GrENEKAL    DESCRIPTION    OF    BASALTS. 

Having  described  the  various  minerals  that  enter  into  the  com- 
position of  the  Kula  basalcs,  we  may  now  take  up  the  general 
description  of  the  rocks  from  the  various  localities,  and  for  this 
purpose  an  arrangement  in  accordance  with  their  chronological 
succession,  as  far  as  is  possible  to  determine  it,  will  be  the  best  to 
follow.  As  I  did  not  collect  any  specimens  of  the  basalts  of  the 
first  period,  we  shall  pass  that  over  and  begin  with  the — 

Second-period  Basalts. — These  are  represented  by  specimens 
from  a  well-digging  in  the  northeast  part  of  the  town  of  Kula,  from 
the  eastern  slope  of  Ai  Tepesi,  from  the  end  of  its  southeast  lava 
stream,  and  from  the  second-period  stream  which  underlies  the 
northern  Kula  Devlit  stream,  at  the  Gediz  Bridge.  The  well  dig- 
ging is,  according  to  my  host,  about  35  metres  deep,  sunk  through 
lava,  and  the  specimens  obtained  came  from  the  lowest  level 
whence  they  had  been  newly  dug.  Below  the  lava  they  find 
"  baked  earth,"  and  strike  water  some  10  metres  down  in  this. 
This  lava  is  of  sp.  gr.  2.733,  rather  rough  in  texture,  but  fine- 
grained, with  few  gas  pores,  and  perfectly  fresh.  Its  color  is  light 
ash-gray,  and  scattered  through  the  rock  are  seen  greenish-yellow, 
glassy,  augite  and  olivine  phenocrysts,  but  very  few  hornblende 
phenocrysts.  The  other  specimens  of  this  period  are  similar,  except 
that  they  are  more  compact  and  the  Ai'  Tepesi  ones  darker.  The 
sp.  gr.  of  the  piece  from  the  slope  of  the  cone  is  2.813,  and  of 
that  from  the  end  of  its  lava  stream  2.721.  This  last  lava  showed 
a  lamellar  structure  resembling  that  of  phonolite. 


TEE   VOLCANOES    OF   THE    KULA    BASIN   IN   LYDIA.         51 

Under  the  microscope  they  are  all  seen  to  belong  to  the  "  nor- 
mal "  basaltic  type,  the  groundmass  being  a  mixture  of  colorless 
glass  and  leptomorphic  feldspar,  with  quite  abundant  colorless  au- 
gite  microlites,  plagioclase  laths  and  magnetite  grains,  which  often 
show  a  fluctuation  structure.  The  porphyritical  generation  is  rep- 
resented by  augite  and  olivine  in  generally  small  crystals",  and 
hornblende.  The  last  is  in  all  these  rocks  most  completely  altered, 
not  a  particle  of  unaltered  hornblende  having  been  seen.  The 
crystals  have  all  gone  over  either  into  a  mass  of  brown  aggregate 
surrounded  by  an  augite-opacite  border  or,  most  frequently,  com- 
pletely into  a  mass  of  augite  and  opacite  grains,  with  very  com- 
monly a  ring  of  larger  opacite  grains  near  the  edge.  (Cf.  PI.  IV, 
Fig.  2.)  The  form  of  the  crystal  is  not  as  well  preserved  as  in  the 
later  lavas,  and  most  of  the  smaller  crystals  have  been  reduced  to 
rounded  forms.  The  relative  proportion  of  glass  is  not  as  great  as 
in  any  of  the  later  rocks,  and  this,  the  larger-grained  structure,  the 
leptomorphic  feldspar,  and  the  perfect  alteration  of  the  hornblende 
may  serve  to  distinguish  the  basalts  of  the  second  period  from 
those  of  the  third.  The  chemical  composition  is  shown  in  Analysis 
I,  page  57. 

Ttiird-period  Basalts. — We  shall  take  up  first  of  these  the  ba- 
salts of  "  Tlie  Knolls."  The  lava  of  which  these  are  composed 
presents  three  distinct  types  of  structure,  which  show  a  gradual 
transition  into  one  another,  they  being  all  glassy.  These  three 
types  may  be  called  hyalopilitic,  semi-vitreous,  and  tachylytic. 

a.  Hyalopilitic. — These  are  all  dark  iron  -  gray  rocks,  of  a 
very  compact  texture,  and  with  few  or  no  gas  pores.  The  sp. 
gr.  of  one  of  them  is  2.704.  Scattered  through  the  mass  of  the 
rock  are  numerous  small,  glistening,  black  hornblende  phenocrysts. 
while  augite  and  olivine  are  seldom  to  be  seen.  Rounded  grains  of 
clear  colorless  quartz  enclosures  are  not  uncommon,  one  of  these 
having  a  length  of  15  mm.  A  few  feldspar  enclosures  are  also 
to  be  seen  in  the  specimens  examined,  and  one  much-decom- 
posed piece  has  cavities  filled  with  a  white  zeolitic  mineral.  This 
piece  is  decomposed  on  the  surface  to  a  dull  chocolate  brown 
mass,  and  veins  of  the  same  color  are  seen  running  through  it. 
The  large  majority  of  the  specimens,  though,  are  quite  fresh  and 
unaltered. 

Under  the  microscope  these  rocks  show  a  highly  typical  hyalo- 


52         THE  VOLCANOES   OF   THE   KULA    BASIN   IN   LYDIA. 

pilitic  groundmass,  of  which  the  basis  is  a  colorless  glass.  This  is 
very  thickly  strewn  with  small  plagioclase  laths,  colorless  microlites, 
and  magnetite  grains,  the  last  two  being  especially  abundant.  In  ad- 
dition to  these  is  also  seen  a  considerable  quantity  of  black  straight 
trichites.  In  some  places  the  groundmass  is  colored  brown  in  long 
streaks  which  run  though  the  colorless  mass.  A  fluidal  arrangement 
of  the  plagioclase  laths  and  augite  microlites,  especially  about  the 
large  phenocrysts,  is  not  uncommon,  but  not  as  well  developed  as 
in  the  more  glassy  varieties  to  be  next  described. 

Phenocrysts  are  quite  abundant,  consisting  of  hornblende, 
augite,  and  olivine.  The  hornblende  is  generally  brown,  these 
rocks  being  quite  deficient  in  the  green  variety.  The  hornblende 
is  almost  invariably  altered,  but  generally  only  as  far  as  the  second 
stage,  where  brown  aggregate  and  a  narrow  augite-opacite  border 
surround  a  core  of  still  unaltered  substance,  and  the  outlines  are 
well  preserved.  The  augite  and  olivine  present  no  special  features 
of  interest.  For  chemical  composition  see  Anal.  II,  page  57. 

b.  Semi-vitreous  Type. — In  this  type  of  the  knoll  basalts  are 
included  two  specimens  from  the  "  ropy  "  stream  east  of  Kara  Tepe, 
which  is  considered  to  belong  to  the  same  period  on  the  ground  of 
the  character  of  its  flow,  and  its  great  resemblance  under  the  micro- 
scope. These  rocks  are  all  iron-black,  occurring  both  in  compact 
and  somewhat  vesicular  varieties,  the  pores  of  the  latter  being  small 
and  not  very  abundant.  They  have  not  the  dull  lustre  of  the  pre- 
ceding rocks,  but  present  a  rather  shining  fracture,  with  a  pitchy 
sub-resinous  lustre.  The  sp.  gr.  of  one  is  2.647.  As  phaenocrysts 
are  seen  many  small  glistening  black  hornblende  crystals,  which,  as 
well  as  the  pores,  are  arranged  in  lines  of  flow.  Crystals  of  augite  or 
olivine  visible  megascopically  are  very  rare.  Though  some  of  the 
specimens  are  decomposed  on  the  surface,  yet  at  a  depth  of  a  few 
mm.  they  are  perfectly  fresh,  moisture  apparently  not  having  been 
able  to  penetrate  at  all. 

Microscopically  these  rocks  show  a  largely  preponderating  light 
cinnamon-brown  glass  basis,  often  mottled  light  and  dark,  and  oc- 
casionally with  streaks  of  a  much  darker  color.  In  this  glass  basis 
are  many  augite  microlites,  plagioclase  laths,  and  magnetite  grains, 
the  microlites  being  by  far  the  most  abundant,  while  the  magnetite 
is  present  in  very  much  smaller  quantity  than  in  the  preceding. 
The  bearing  of  this  fact  on  the  crystallization  period  of  the  mag- 
netite has  been  already  discussed.  The  plagioclase  crystals,  while 


THE    VOLCANOES    OF  THE   KULA   BASIN   IN   LYDIA.         53 

fewer  in  number  than  in  the  hyalopilitic  variety,  are  rather  larger 
and  better  developed.  The  black  trichites  seem  to  be  entirely 
wanting.  The  microlites  and  plagioclase  crystals  show  frequent 
flnidal  structure.  (Of.  PI.  IV,  Fig.  1.) 

The  pheuocrysts  are  hornblende  and  augite,  with  only  rarely 
olivine.  The  hornblende  is  commonly  brown,  but  green  crystals 
are  also  seen.  Both  are  usually  fresh,  and  when  alteration  has 
taken  place  it  has  nearly  always  only  reached  the  brown-aggregate 
stage.  The  augite  is  in  small  colorless  and  very  bright  crystals, 
fairly  well  developed,  An  analysis  of  this  type  was  not  made,  but 
compare  Analysis  VI.  of  a  Kara  Tepe  lava,  which  very  closely 
resembles  this  type. 

c.  The  tachylytes*  occur  chiefly  as  streaks  in  the  semi-vitreous 
lavas,  often  forming  the  upper  surface,  but  one  "  knoll"  was  com- 
posed almost  entirely  of  this  variety.  They  are  very  compact  jet- 
black  rocks,  with  a  vitreous  lustre.  In  some  places  they  have  ac- 
quired through  slight  surface  oxidation  an  iridescent  tarnish,  which, 
with  their  color  and  lustre,  gives  them  an  anthracitic  appearance. 
The  sp.  gr.  of  two  specimens  was  found  to  be  2.695  and  2.747.  The 
latter  is  strangely  high  for  so  glassy  a  rock,  and  a  mistake  is  possible. 
As  crystallizations  are  to  be  seen  microscopically  a  few  small  black 
hornblende  crystals,  and  very  rarely  a  small  augite.  One  specimen 
contains  on  the  surface  a  few  spots  of  white  zeolitic  mineral,  and  a 
small  quartz  enclosure. 

Under  the  microscope  they  are  seen  to  consist  almost  entirely  of 
a  clear  dark  chocolate-brown  glass,  with  streaks  of  a  darker  and 
dusty  material  which  show  the  fluidal  structure  very  finely.  There 
are  also  present  a  few  augite  microlites,  very  few  small  plagioclase 
and  augite  crystals,  and  streaks  of  dark  dusty-brown  material  which 
aid  in  bringing  out  the  fluidal  structure.  Magnetite  is  practically 
entirely  absent,  and  no  perlitic  cracks  are  seen.  As  phenocrysts 
there  are  present  hornblende  in  rather  large  crystals,  both  brown 
and  green,  often  showing  zonal  structure,  but  always  clear  and  un- 
altered. Large  crystals  of  colorless  augite,  but  very  little  olivine, 
are  also  present.  These  rocks  on  the  whole  are  beautiful  examples 
of  tachylytes,  and  form  Borne  of  the  prettiest  slides  of  the  series. 
An  analysis  of  one  is  given  in  No.  Ill,  page  57. 

*  They  are  decomposed  by  hot  HC1  with  separation  of  gelatinous  silica  on 
cooling,  and  so  are  true  tachylytes. 


54     '  THE   VOLCANOES    OF   THE    KULA   BASIN   IN   LYDIA. 

Southwest  Stream. — This  stream  is  composed  of  a  dark  ash- 
gray,  very  compact  and  tough  basalt,  showing  few  or  no  pores.  The 
sp.  gr.  of  one  specimen  proved  to  be  2.613.  A  few  very  small 
hornblende  crystals  and  still  fewer  augite-olivine  crystals  are  to  be 
seen,  and  the  specimens  are  all  perfectly  fresh. 

Under  the  microscope  they  are  all,  with  one  or  two  exceptions, 
of  the  regular  hyalopilitic  structure,  with  a  colorless  glass  basis. 
Microlites  and  magnetite  grains  are  very  abundant,  the  plagioclase 
less  so.  The  hornblende  is  dark  brown  and  most  of  it  has  under- 
gone alteration  to  brown  aggregate,  occasionally  having  reached  the 
last  stage.  The  remarks  made  under  the  head  of  the  hyalopilitic 
knoll  basalts  apply  equally  well  here,  as  the 'rocks  seem  almost 
identical. 

The  two  exceptions  above  spoken  of  belong  to  the  semi-vitreou& 
type,  with  brown  glass  basis,  and  are  like  the  corresponding  knoll 
rocks  except  for  one  peculiarity.  This  is  the  presence  of  spots  of 
colorless  glass,  from  0.1-0.3  mm.  in  diameter,  generally  round  in 
shape,  but  often  quite  irregular.  These  spots  contain,  besides 
microlites  and  magnetite  grains,  many  straight  black  trichites, 
which  are  commonly  arranged  in  a  roughly  radial  manner.  This 
colorless  glass  is  surrounded  by  a  ring  of  brown  glass  much  darker 
than  the  rest  of  the  groundmass,  but  shading  gradually  into  it,  and 
containing  the  usual  groundmass  microlites,  etc.  These  spots 
might  be  mistaken  for  leucite,  but  their  size,  the  irregularity  of 
their  form,  the  fact  that  plagioclase  needles  were  seen  lying  both 
in  the  colorless  glass  and  in  the  brown  ring,  and  the  brown  ring 
itself  all  show  that  they  are  not  leucite.  Hatch  *  observed  and 
figured  similar  objects  from  a  Madagascar  basalt.  They  are  appar- 
ently due  to  small  local  development  of  iron-rich  black  trichites,. 
with  concomitant  repulsion  of  the  unused  iron  from  their  midst, 
forming  the  ring. 

North  Stream. — This  and  the  following  stream  offer  a  special 
feature  of  interest  inasmuch  as  they  are  both  leucitic.  The  rock  of 
which  this  stream  is  composed  is  light  gray  and  compact,  but  mostly 
with  numerous  small  gas-pores  arranged  in  streaks,  showing  the  flow 
structure.  The  sp.  gr.  of  one  specimen  is  2.711.  Practically  no 
hornblende  is  to  be  seen  macroscopically,  but  augite  and  olivine 
phenocrysts  are  abundant. 

*  Hatch,  Rocks  from  Madagascar,  loc.  cit.  p.  350. 


THE    VOLCANOES.  OF   THE    KULA    BASIN    IN    LYDIA.         55 

Under  the  microscope  they  show  a  hyalopilitic  structure,  the 
glass  basis  being  always  colorless.  Microlites  and  magnetite  grains 
are  very  abudant,  but  plagioclase  is  rare  compared  with  the  pre- 
ceding hyalopilitic  rocks.  These  small  bodies  frequently  show  a 
fluctuation  structure,  especially  around  the  large  phenocrysts. 

These  phenocrysts  are  hornblende,  which  is  always  altered,  gen- 
erally to  the  last  two  stages,  augite  and  olivine  in  clear  colorless 
crystals  and  fragments,  and  leucite,  which  is  quite  abundant  in 
streaks  and  patches.  The  crystals  are  small,  but  very  characteristic 
and  unmistakable.  The  description  given  farther  back  covers  all 
the  points  of  interest,  so  nothing  further  need  be  said  here. 
Analysis  IV  shows  the  composition  of  these  rocks. 

Southeast  Stream. — This  stream,  as  before  mentioned,  seems  to 
be  made  up  of  two  distinct  streams,  one  above  the  other,  which  have 
been  poured  out  since  the  period  of  the  knolls,  the  lower  one  being 
more  compact  and  with  a  tendency  to  columnar  structure.  How- 
ever, as  the  two  seem  identical  petrographically,  they  will  be 
described  together,  a  few  words  sufficing,  as  they  greatly  resemble 
the  rocks  of  the  north-stream.  These  rocks  are  dark  gray,  those 
of  the  lower,  stream  quite  compact,  those  of  the  upper  vesicular. 
They  show  few  crystals  of  hornblende,  but  macroscopic  crystals  of 
augite  and  olivine  are  rather  abundant.  Three  different  specimens 
had  sp.  grs.  of  2.712,  2.715,  2.736. 

Microscopically  they  are  hardly  to  be  distinguished  from  the 
north-stream  basalt,  being  of  the  same  hyalopilitic  structure  and 
containing  leucite  in  addition  to  the  usual  constituents.  The 
leucite  calls  for  no  special  comment,  exactly  resembling  the  occur- 
rence just  described.  Analysis  V  is  of  a  specimen  from  this  stream. 

Kara  Tepe  Stream. — Specimens  Avere  collected  from  the  well- 
defined  lava  stream  of  Kara  Tepe  at  three  different  points :  at  the 
bottom  of  the  crater,  at  a  point  about  one  hundred  metres  down 
the  stream,  and  again  some  fifty  metres  below  this.  No  difference 
however,  is  to  be  seen  among  them,  either  megascopically  or  micro- 
scopically. They  are  all  iron-black  compact  rocks  with  numerous 
fine  pores  and  a  sub-greasy  lustre.  The  sp.  gr.  of  one  is  2.604. 
Small  shining  black  hornblendes  are  very  abundant,  and  are  gener- 
ally arranged  in  lines  of  flow.  Augite  and  olivine  are  rarely  seen. 

Microscopically  they  show  a  groundmass  of  light,  unmottled, 
cinnamon-brown  glass,  with  numerous  colorless  augite  microlites, 
some  magnetite  grains,  and  not  very  abundant  small  plagioclase 


56        THE  VOLCANOES   OF  THE   KULA   BASIN   IN    LYDIA. 

crystals.  These  last  are  much  larger  than  usual  and  better  crystal- 
lized. They  nearly  all  show  twinning  lamellae,  and  it  was  in  these 
rocks  that  optical  investigation  of  the  plagioclase  was  possible. 
Otherwise  the  groundmass  resembles  closely  that  of  the  semi-vitreous 
knoll  basalts. 

The  phenocrysts  are  mostly  hornblende,  which  is  here  fre- 
quently green,  these  rocks  being  far  richer  in  this  variety  than  any 
of  the  others.  The  hornblende  is  generally  unaltered,  but  Avhen  such 
is  not  the  case  the  alteration  generally  only  reaches  the  brown-aggre- 
gate stage,  with  a  kernel  of  hornblende.  The  augite  and  olivineare 
not  common,  but  in  these  rocks  the  hour-glass  and  similar  struct- 
ures are  very  common  among  the  augites,  most  of  them  showing 
phenomena  of  the  sort.  The  chemical  constitution  is  shown  in 
Analysis  VI. 

ScoricB. — Specimens  of  scoriae  and  lapilli  were  collected  from 
the  craters  of  Kula  Devlit  and  Kara  Tepe.  They  are  generally 
black^but  sometimes  red  or  brown  from  decomposition.  They  are, 
of  course,  very  vesicular  and  spongy.  Megascopical  crystals  are 
rarely  to  be  seen. 

They  all  show  under  the  microscope  a  basis  of  dark-brown — 
occasionally  red-brown — glass  containing  many  augite  microlites  and 
plagioclase  laths.  Magnetite  is  very  rare,  but  occasionally  a  fine 
brown  "dust"  is  present.  Hornblende  occurs  in  large  crystals  both 
brown  and  green,  frequently  zonally  colored,  and  often  showing  the 
alteration  to  a  dark  red-brown  variety.  Augite  and  olivine  crystals 
are  also  present,  and  in  one  specimen  from  Kula  Devlit  leucite,  in 
crystals  exactly  resembling  those  described  above,  was  found.  It 
was  noticed  that  the  inner  surface  of  many  of  the  vesicles  was  coated 
with  a  thin  layer  of  colorless  or  light-yellow  substance,  which  showed 
in  some  places  a  weak  aggregate  polarization. 

Chemical  Analyses. — The  analyses  on  p.  57  were  made  for  me 
by  Dr.  A.  Rohrig  of  Leipzig. 

From  these  analyses  it  will  be  seen  that  these  rocks  belong  to 
the  more  acid  basalts  and  that  they  show  a  most  marked  similarity 
with  one  another.  The  composition  is  a  normal  basaltic  one,  the 
Si02  being  rather  high,  the  A120S  (also  in  rather  high  percentage) 
coming  next  in  relative  amount,  the  percentage  of  MgO  being  less 
than  that  of  CaO,  and  that  of  K20  less  than  that  of  Xa20.  The 
generally  high  percentagetof  Na20  points  to  the  presence  of  nephe- 
line,  but  treatment  of  some  of  the  slides  with  acid  gave  negative 


THE    VOLCANOES    OF   THE    KULA    BASIN    IN    LYDIA.         57 


I. 

II. 

ni. 

IV. 

V. 

VI. 

H2O  (Ignit)  0.02 
SiO2.  48.24 
A12O3  2064 

0.46 
47.50 
19.32 

0.12 
47.79 
18  52 

0.48 
47.97 
20  04 

0.04 

47.74 
20  95 

0.30 
47.58 
20  36 

FesO,  4.63 
FeO     .                       5  55 

4.75 
5  20 

4.65 
5  47 

4.45 
5  50 

3.29 
6  32 

3.78 
5  45 

•CaO         ...               7  94 

8  37 

8  34 

7  64 

7  56 

8  31 

MgO  ...                     5  02 

4  36 

5  31 

5  54 

5  16 

5  28 

Na2O     .                     5  08 

763 

7  66 

5  14 

71'-* 

6  49 

KQO  1  88 

2  31 

0  69 

1  99 

1  21 

1  33 

P2O6  0  97 

0  21 

0  13 

99.97 

100.11 

98.55 

98.75 

99.52 

98.88 

Sp.gr  j       2.733 

i 

2.704 

2.695 

$.711 

2.736 

2.604 

results,  and  this  mineral  seems  to  be  absent,  contrary  to  the  usual 
composition  of  hornblende  basalts.  That  all  the  specimens  were  fresh 
is  shown  by  the  very  small  ignition  loss.  With  the  above  analyses 
I,  II,  III,  and  VI  may  be  compared  the  analyses  of  basalts  from  the 
Cascade  Mountains,  Oregon;  Ferdinandea  Islands;  and  the  ^Etna 
lavas  of  1766  and  1802,  as  quoted  by  Roth.*  A  striking  feature  is 
the  very  small  percentage  of  K20  shown  in  analyses  IV  and  V  of 
the  leucitic  north  and  southeast  streams.  The  leucite  is  seen  under 
the  microscope  to  be  present  in  not  very  great  abundance,  yet  a 
higher  percentage  of  KaO  was  expected.  Zirkelf  in  his  work  on 
basalts  describes  similar  cases,  and  remarks  that  it  is  not  absolutely 
necessary  for  a  leucitic  basalt  to  be  distinguished  by  a  high  K20 
percentage. 

A  word  in  regard  to  the  specific  gravities:  While  they  are  all 
rather  low  for  basalt,  yet  this  is  to  be  explained  by  their  very  large 
glass  content.  It  will  have  been  noticed  also  that,  with  the  excep- 
tion of  the  tachylytes,  whose  specific  gravities  are  curiously  high, 
the  figures  show  a  pretty  regular  gradation  from  the  least  to  the 
most  glassy.  For  the  purpose  of  more  ready  comparison  the  table 
on  p.  58  is  inserted.  The  determinations  were  all  made  with  a 
Thoulet's  solution  and  a  Westphal's  balance  at  15°  C. 


*  Roth,  Beitr.  z.  Petrog  d.  pluton.  Gesteine.  Berliu,  1884.  Dolerit  uud, 
Dolerit  basalt,  Nos.  11,  15,  31,  and  29. 

f  Zirkel,  Bt-sultgesteiue,  p.  191.  Cf.  Iddiugs,  Origin  Ign.  Rocks,  I.  c. 
p.  166. 


58 


VOLCANOES    OF   THE    KULA    BASIN    IN    LYDIA. 


^^ariety. 

Specific  Gravities. 

Average. 

2.813,  2.733,  2.721 
2.736,  2.715,  2.712,  2.711 
2.704,  2.647,  2.613 
2.604 
2.747,  2.695 

2.756 
2.719 
2.655 
2.604 
2.721 

Hyalopilitic  bnsalt 
Hyalopilitic 
Semi-vitreous    " 
Tachylytes  

s  (Leucitic)  
(Leucite-free)  .  . 

General  Conclusions. — -Having  now  described  the  Kula  basalts  it 
remains  for  us  to  make  a  few  general  remarks  on  them : 

That  they  form  a  good  example  of  a  "petrographical  province," 
as  before  spoken  of,  the  reader  will  now  see  for  himself,  but,  of 
course,  this  fact  come*  out  more  clearly  from  a  microscopic  exami- 
nation of  the  rocks  themselves  than  from  any  description.  The 
most  striking  feature  about  them  is  the  unfailing  presence  of  basal- 
tic hornblende,  and  its  peculiar  alteration  products.  As  stated 
before,  the  hornblende,  as  regards  constancy,  invariability,  and  quan- 
tity, surpasses  the  augite,  olivine,  or  feldspar,  and  here  plays  the 
leading  role,  and  not  a  subsidiary  one  as  in  other  hornblende-bearing 
basalts.  So  much  so  is  this  the  case,  that  here  I  feel  justified  in 
grouping  the  Kula  and  similar  basalts  together  as  a  sub-group,  and 
giving  them  a  separate  name,  although  thinking  that  a  too  free  use- 
of  new  names  is  rather  a  hindrance  than  a  help  to  science.  The 
name  which  first  suggests  itself,  and  which  on  consideration  seems 
most  appropriate,  is  Kulaite.  By  this  we  understand  a  sub-group 
of  the  basalts — either  plagioclase-,  nepheline-,  or  leucite-, — which  is 
characterized  by  the  invariable  presence  of  hornblende  as  an  essen- 
tial constituent,  which  also,  both  in  quantity  and  invariability,  sur- 
passes the  augite;  in  other  words,  to  a  large  extent  replaces  the 
latter.  We  can  have  the  further  subdivisions  of  leucite-kulaite,  and 
nepheline-kulaite. 

The  gradual  transition  shown  from  the  least  to  the  most  crystal- 
line, and  the  constancy  of  the  chemical  composition  in  all  of  them, 
are  also  interesting.  The  leucite-kulaites  seem,  however,  to  have 
been  among  the  last  poured  out  by  Kula  Devlit,  though  from  Kara 
Tep6,  a  very  short  distance  off,  came  at  a  probably  later  date  a  leu- 
cite-free  kulaite.  The  whole  region  must,  however,  be  more  care- 
fully examined  before  entering  into  a  discussion  of  this  and  other 
points.  The  writer  therefore  defers  further  remarks  and  the  bring- 
ing up  of  other  points  till  after  an  exploration  of  the  region  in  the 
spring  of  1894,  which  he  hopes  to  accomplish. 


THE   VOLCANOES   OF   THE    KULA    BASIN    IN    LYDIA.         59 


ENCLOSURES.* 

But  besides  the  kulaites  we  must  describe  the  quite  numerous 
enclosures  of  foreign  minerals  and  rock  which  were  found  in  them. 
These  fall  under  two  heads: 

1st.  Generally  small  enclosures,  chiefly  of  quartz  and  plagio- 
clase,  which  show  signs  of  great  alteration,  and  are  rather  in- 
timately associated  with  the  basalt,  perhaps  endogenous  enclosures. 

2d.  Masses  of  foreign  rock  which  have  to  a  large  extent  pre- 
served their  original  form  and  structure,  and  which  do  not  show 
intimate  association  with  the  kulaite, — exogenous  enclosures. 

These  two  groups  represent  different  original  rocks,  and  are  in 
no  way  connected  with  one  another. 

Endogenous  (?)  Enclosures. — These  all  have  rounded  outlines,  and 
many  have  been  melted  after  being  enclosed  in  the  stream.  The  ma- 
jority of  them  are  quartz  and  plagioclase,  but  enclosures  of  orthoclase 
and  a  fibrous  mineral  were  also  seen.  Enclosures  of  one  or  the  other 
of  these  kinds  were  found  in  specimens  from  all  the  streams,  except 
tho'se  of  the  second  period.  As  fewer  specimens  of  these  were  col- 
lected, it  is  possible  that  they  will  also  be  found  here  on  further 
search.  About  twenty  were  to  be  found  in  the  slides,  and  about  a 
dozen  were  seen  megascopically. 

Quartz  Enclosures. — These  are  quite  numerous,  and  most  of  the 
megascopically  visible  enclosures  belong  here.  One  of  them  meas- 
ures 15  mm.  long.  They  are  perfectly  clear,  colorless  or  with  a 
tinge  of  yellow,  rounded  in  shape,  and  much  cracked. 

Under  the  microscope  they  show  the  usual  features  of  quartz  en- 
closures in  eruptive  rocks.  They  are  clear,  somewhat  cracked,  and 
are  frequently  melted  to  a  colorless  or  rarely  light-brown  glass. 
Occasionally  a  kernel  of  unmelted  quartz  remains  in  the  centre,  but 
most  of  them  are  completely  melted.  The  glass  has  the  usual 
fringe  of  greenish  augite  needles  round  the  edge,  all  of  them  point- 
ing radially  inward.  The  extinction-angle  of  these  microlites  is  about 
40°.  One  such  enclosure  contained  inclusions  of  many  small 

*  As  a  distinction  seems  advisable  between  essential  mineral  components 
of  a  rock  which  are  included  in  larger  crystals,  and  fragments  of  foreign 
bodies — either  altered  or  not — which  have  become  enclosed  in  the  lava  stream 
during  its  flow,  I  use  throughout  this  paper  the  words  "inclusion"  for  the 
former  ciise  and  "enclosure"  for  the  latter. 


60        THE  VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA. 

(0.005-0.01  mm.),  sharply  crystallized  green  octahedra  of  spinel. 
Another — completely  vitrified  and  with  large  augite  microlites — 
was  seen  as  an  inclusion  in  a  large  augite  crystal. 

Plagioclase  Enclosures, — These  are  also  numerous  and  quite 
large,  some  reaching  a  diameter  of  4  or  5  mm.,  when  they  can 
be  readily  distinguished  without  the  lense.  Under  the  microscope 
they  appear  as  colorless  masses  of  irregular  outline.  They  all  show 
twinning  lamellae,  and  two  of  these  which  had  nearly  symmetrical 
extinction  gave  angles  of  7°  30'  and  8°  10',  corresponding  to  labra- 
dorite  of  about  the  composition  Ab3An5.  In  some  cases  these 
plagioclase  masses  have  apparently  been  melted,  as  one  or  two  were 
seen  containing  crystals  of  hornblende  exactly  similar  in  size,  color, 
and  stage  of  alteration  reached  to  the  neighboring  ones  in  the  kulaite. 
Others,  again,  show  at  the  edges  a  narrow  border  of  secondary  feld- 
spar crystals  arranged  radially.  Here  the  periphery  of  the  plagio- 
clase enclosure  has  evidently  been  melted,  and  has  recrystallized  in 
a  new  form  in  accordance  with  its  changed  conditions.  This  fusion 
may  have  taken  place  at  the  moment  of  solidification,  when  a  rise 
in  temperature  took  place.  Several  of  them  contain  apatite  in 
short  colorless  or  bluish-gray  prisms,  often  with  dusty  inclusions. 

In  addition  to  the  hornblende  and  apatite  most  of  these  enclos- 
ures include  several  minerals  of  secondary  origin,  their  formation 
being  due  to  the  metamorphic  action  of  the  molten  basalt.  These 
secondary  minerals  are  dark  olive-green  spinels,  which  are  very 
common,  sillimanite  needles,  and  biotite.  One  plagioclase  enclos- 
ure deserves  especial  description  on  account  of  the  number  and  va- 
riety of  its  secondary  inclusions.  This  was  in  a  specimen  from  the 
latest  southeast  stream,  and  consists  of  a  clear  mass  of  plagioclase 
showing  very  few  twinning  lamellae.  Green  spinels  are  scattered 
through  it,  but  are  chiefly  clustered  together  in  a  long  streak. 
Near  this  is  a  group  of  small  violet-gray  isotropic  crystals  of  perof- 
skite.  Through  a  great  part  of  the  feldspar  runs  a  stream  of  silli- 
manite needles,  lying  parallel  to  one  another  and  the  direction  of 
the  streak.  A  few  irregularly  shaped  brown  biotite  flakes  are  scat- 
tered through  the  mass,  and  in  one  corner  are  seen  two  or  three 
glass  inclusions  of  probably  secondary  origin,  consisting  of  a  ring 
of  very  pale-brown  glass  (0.02  mm.  in  diameter)  with  a  bubble 
in  the  centre. 

Ortliodase  and  Fibrous  Enclosures. — Of  the  former  only  two 
were  seen.  They  are  rounded  in  outline,  and  the  feldspar  is 


THE   VOLCANOES    OF   THE   KULA   BASIN   IN   LYDIA.         61 

mostly  clear,  but  is  cloudy  and  opaque  on  the  edges  and  along 
cracks.  Several  small  rounded  masses  of  colorless  fibres  were  "ob- 
served, which  show  aggregate  polarization.  What  this  mineral  is 
could  not  be  determined,  but  it  is  neither  sillimanite  nor  zoisite. 
In  one  case  a  few  brown  spinels  were  included,  and  some  clear 
light-brown  glass  was  seen  between  the  fibres. 

These  enclosures  may  represent  a  primary  separation  of  some 
constituents  of  the  magma,  though  the  habit  of  the  quartz  grains 
points  rather  to  exogenous  enclosures.  In  this  latter  case  the 
original  rock  would  have  been  a  quartz  diorite.  No  such  rock  is 
mentioned  by  Tchihatcheff  as  occurring  in  the  vicinity,  and  none 
was  seen  by  me.  For  occurrences  of  quartz  in  basalt  see  note.* 

Exogenous  Enclosures. — Several  cases  were  seen  of  fragments  of 
foreign  rock  enclosed  in  the  lava,  and  of  these  three  specimens 
were  brought  back  for  examination.  One  comes  from  the  west 
inner  wall  of  the  Kula  Devlit  crater,  and  the  other  two  from  blocks 
in  the  latest  southeast  stream.  Though  the  last  two  are  much 
decomposed  by  the  action  of  the  atmosphere,  they  all  seem  to  be 
fragments  of  the  same  original  rock,  and  we  shall  describe  the 
crater  specimen  as  the  typical  and  best-preserved  example. 

Macroscopically  this  is  a  fine-grained  compact  rock,  of  general 
grayish  color,  though  on  closer  examination  it  is  seen  to  be  made 
up  of  white,  greenish-gray,  and  brownish  grains. 

Microscopically  it  is  seen  to  be  holocrystalline,  with  medium- 
grained  granitic  structure,  composed  chiefly  of  rounded  xeno- 
morphic  augite,  quartz,  and  orthoclase  grains,  and  seems  to  be  an 
augite  granite. 

The  augite  grains  are  colorless,  but  here  and  there  colored  yel- 
lowish green  through  chloritic  decomposition.  The  cleavage  is  very 
well  marked,  the  relief  high,  and  the  polarization  colors  the  usual 
bluish  gray  and  yellowish.  Inclusions  of  small  zircons  were  some- 
times seen. 

The  quartz  is  sometimes  cracked,  but  clear,  and  much  of  it  acts 
as  a  cement  for  the  other  grains.  As  inclusions  were  seen  small 
magnetite  grains  and  a  few  glass  specks,  but  no  liquid  inclusions 
or  bubbles  were  noticed.  A  few  small  augites  and  zircons  are  also 
included. 


*Iddings,  Am.  J.  Sci.  xxxvi,  1888,  208;  Bull.  U.  S.  Geol.  Survey,  No.  66, 

1890. 


62        THE   VOLCANOES   OF  THE   KULA   BASIN   IN    LYDIA. 

The  orthoclase  grains  are  perfectly  fresh,  as  a  rule,  and  present 
no  specially  interesting  features.  In  some  places  it  is  kaolinized 
and  cloudy.  Besides  the  orthoclase,  a  few  clear  plagioclase  grains 
were  seen,  distinguishable  by  their  twinning  lamellae. 

In  addition  to  the  above,  zircon  and  iron  ores  are  present.  The 
former  is  in  small  hair  brown  crystals,  some  showing  the  bi-pyramid 
a;(311).  The  pleochroism  is  very  distinct,  being  colorless,  or  of  a 
very  faint  greenish  tinge  parallel  to  6,  and  dark  brown  parallel  to  a. 
The  ores  are  magnetite  and  ilmenite,  the  latter  being  distinguished 
by  the  mantle  of  leucoxene.  They  form  irregular  black  grains  and 
show  the  lustre  very  distinctly. 

In  one  place  in  the  slide  is  seen  a  fissure  filled  with  colorless 
glass  which  contains  some  zircons  and  is  much  crack-eel. 

The  rock  on  the  whole  shows  extremely  few  signs  of  alteration 
due  to  the  action  of  the  basalt.  The  weathered  specimens  have  been 
altered  to  masses  of  calcite  and  kaolin,  with  here  and  there  augite 
and  quartz  grains.  Some  spots  of  extremely  pale  brown  glass  with 
a  network  of  fine  veins  of  colorless  glass  running  through  them  were 
seen  in  these  specimens. 

Like  the  diorite  no  such  rock  is  known  in  the  vicinity  as  a  sur- 
face occurrence,  but  to  judge  from  the  slight  alteration  it  has  un- 
dergone both  in  form  and  structure,  it  is  probable  that  this  rock 
lies  quite  close  to  the  surface. 

On  further  consideration  it  has  occurred  to  me  that  K.  Mallet's 
theory  of  the  origin  of  volcanic  energy  may  explain  the  difference 
in  the  state  of  alteration  of  the  two  kinds  of  enclosures  on  the  sup- 
position that  the  so-called  "endogenous"  enclosures  are  in  reality 
exogenous.  Mallet*  ascribes  the  heat  shown  in  volcanic  phenomena 
to  pressure  between  two  parts  of  the  earth's  crust,  caused  by  tan- 
gential strains  consequent  on  the'contraction  of  the  crust  during  the 
earth's  secular  cooling.  He  shows  that  this  heat  would  be  most 
developed  along  cracks  or  other  lines  of  weakness,  and  further  that 
the  heat  would  be  greater  the  greater  the  resistance  to  pressure ; 
for  instance,  the  crushing  of  a  granite  evolving  much  more  heat 
than  that  of  a  sand-stone.  He  further  shows  that  sufficient  heat 
is  developed  by  the  secular  cooling  of  the  globe  to  much  more 
than  account,  with  the  presence  of  water  at  the  point  of  origin,  for 
all  the  volcanic  phenomena  observed.  Here,  it  seems  to  me,  we  have 

*  R.  Mallet,  On  Volcanic  Energy.     Phil.  Trans.  1873,  147. 


THE   VOLCANOES   OF   THE    KULA    BASIN    IN    LYDIA.         t)3 

n  possible  explanation  of  the  greatly  altered  and  disintegrated  con- 
dition of  the  so-called  "  endogenous  "  enclosures,  they  being  remains 
of  the  rock  which  was  crashed  and  melted  at  or  near  the  point  of 
greatest  pressure,  where,  on  the  entrance  of  water,  the  eruption  was 
started.  They  would  hence  have  been  subjected  to  peculiar  condi- 
tions, entirely  different  from  the  "  exogenous  "  enclosures,  which  may 
be  supposed  to  come  from  the  walls  of  the  conduit,  fragments  caught 
in  the  lava  stream  during  its  ascent.  The  above  idea  is  put  forward 
as  a  possibility,  and  no  stress  is  laid  upon  it. 


MISCELLANEOUS  EOCKS. 

Besides  the  lavas  of  the  region  some  other  rocks  were  collected 
and  may  now  be  briefly  described. 

Mica  Schist. — This  was  obtained  from  the  foot-hills  to  the  west  of 
Kula,  and  is  an  ordinary  yellowish-gray,  glistening  foliated  schist. 

Under  the  microscope  it  is  seen  to  be  composed  almost  entirely 
of  muscovite  flakes,  with  some  orthoclase  between  the  crystals  act- 
ing as  cement,  and  in  grains,  and  a  few  zircons  and  quartz  grains. 
Several  long  greenish-gray  tourmalines  were  also  seen.  It  calls  for 
no  further  remark. 

Hornblende  Schist. — The  specimen  was  obtained  from  near  Azi 
Koi,  about  an  hour  and  a  half  from  Ala  Shehir,  on  the  south  slope 
of  the  Konurja  Mountains.  It  is  a  very  fine-grained,  compact  rock, 
banded  in  structure,  the  bands  being  alternately  dark  green  and 
white. 

Under  the  microscope  the  white  bands  are  seen  to  be  composed 
of  many  rounded  orthoclase  and  some  quartz  grains,  a  few  plagio- 
clase  grains  with  twinning  lamellae,  and  many  small  colorless  zir- 
cons which  are  arranged  parallel  to  the  banded  structure.  Small 
flakes  of  brown  biotite  are  also  met  with. 

The  dark  bands,  on  the  other  hand,  show  an  abundance  of  dark 
grayish-green  hornblende  grains,  mixed  with  the  orthoclase  grains. 
These  are  strongly  pleochroic  as  follows:  c  =  dark  grayish  green  ; 
b  =  yellowish  green  ;  a  =  pale  greenish  gray.  These  grains  are 
arranged  with  their  c  axes  parallel  to  the  bands.  Some  of  them 
are  of  a  blue  color,  and  may  be  referred  to  glaucophane.  Small 
zircons  abound  and  somej  colorless  garnets,  generally  arranged  in 


64         THK    VOLCANOES    OF   THE    KTILA    BASIN    IN    LYDIA. 

clusters  and  often  showing  crystal! ographic  planes,  are  present. 
The  biotite  flakes  are  also  not  wanting,  but  they  are  scarce. 

Diabase. — About  fifteen  minutes  below  the  first  Turkish  guard- 
house on  the  southern  slope  of  the  Konurja  Mts.  was  found  a  dike 
about  5  metres  wide  in  the  schist.  The  rock  is  of  a  dark  greenish 
color,  very  fine  grained  and  compact.  Some  crystals  of  brown 
diallage  and  white  feldspar  are  to  be  seen. 

Under  the  microscope  the  rock  seems  to  be  a  much-altered 
diabase,  containing  diallage,  and  shows  the  following  composition  : 
The  structure  was  originally  rather  porphyritic,  and  what  was  the 
groundmass  and  augite  has  now  become  a  mass  of  pale  grayish 
green,  slightly  pleochroic  hornblende  grains,  grouped  irregularly 
and  bedded  in  a  mass  of  feldspar,  most  of  which  is  plagioclase,  but 
of  which  some  is  orthoclase.  In  the  hornblende  clusters  are  large 
irregular  grains  of  magnetite,  and  through  all  this  groundmass  are 
scattered  needles  of  apatite  and  clusters  of  colorless  garnets.  A  few 
brown  biotite  flakes  are  also  present. 

The  porphyritical  crystals  of  feldspar,  while  preserving  their 
form  fairly  well,  have  suffered  much  alteration  ;  being  filled  with  a 
felt  of  sillimanite  needles,  which  is  especially  thick  towards  the 
centre.  Between  the  needles  are  many  grains  of  zoisite  showing  a 
fine  blue  polarization  color.  Biotite  flakes  and  a  few  small  magnetic 
grains  are  included. 

The  diallage  occurs  in  crystals  from  2-4  mm.  long  of  a  gray- 
brown  color.  They  are  frequently  filled  with  thick,  dust-like 
inclusions,  and  some  show  a  dark-brown  core,  then  a  lighter  zone, 
and  at  the  outside  a  dark-gray  border  filled  with  "dust."'  One 
crystal  has  as  an  inclusion  a  large  unaltered  plagioclase  crystal.  The 
extinction  angle  in  one  case  was  30°.  The  crystals  are  generally 
surrounded  by  a  ring  or  border  of  green  hornblende  grains. 

This  diallage  seems  to  be  about  the  only  mineral  which  has  not 
undergone  profound  alteration  and  is  not  secondary — the  horn- 
blende, sillimanite,  zoisite,  biotite,  magnetite,  and  probably  the 
garnet  and  some  of  the  feldspar  being  of  secondary  origin.  The 
completeness  of  the  change  is  striking — the  augite  having  com- 
pletely disappeared,  and  being  changed  into  the  masses  of  granular 
hornblende,  and  the  feldspar  undergoing  an  alteration  similar  to 
saussuritization,  though  with  less  loss  of  form.  The  rock  reminds 
one  of  an  altered  diabase  from  Assnan,  in  Egypt,  where  also  the 


THE   VOLCANOES   OF  THE   KULA   BASIN   IN   LYDIA.         65 

uugite  has  been  changed  into  the  same  green  granular  hornblende, 
with  some  uralite,  and  the  feldspar  to  zoisite,  but  no  sillimanite. 

Serpentine. — A  narrow  vein  of  light  green  serpentine  was  found 
in  the  limestone  near  the  end  of  the  north  stream.  It  offers,  how- 
ever, no  special  features  of  interest,  showing  under  the  microscope 
a  mass  of  colorless  or  pale  green  serpentine  fibres,  with  a  few  mag- 
netite grains.  No  olivine  was  seen. 


VITA. 

I,  HENRY  STEPHENS  WASHINGTON,  was  born  on  January  15, 
1867,  in  Newark,  New  Jersey,  United  States  of  America,  my 
parents  being  George  Washington  and  Eleanor  Washington  (nee 
Stephens).  After  due  preparation  at  home  and  at  school  I  entered 
Yale  College  (now  University)  at  New  Haven,  Conn.,  from  which, 
at  the  end  of  the  regular  four  years'  course,  I  graduated,  with  a 
special  honor  in  Natural  Sciences,  as  B.  A.  in  1886.  I  spent  the 
following  two  years  in  study  at  Yale  University,  during  which  I 
held  for  a  year  the  Silliman  Fellowship  in  Physics,  and  took  the 
degree  of  M.A.  in  June  1888.  The  next  four  years  were  spent 
chiefly  in  travelling  in  the  West  Indies,  Europe,  Egypt,  Algeria, 
Asia  Minor,  etc.,  parts  of  four  winters  and  springs  being  passed 
in  Greece,  where  I  became  a  member  of  the  American  School  of 
Classical  Studies,  and  assisted  in  and  conducted  excavations  in 
Attica  and  at  Plataea,  Argos,  and  Phlius.  The  winter  semesters  of 
1891-92  and  1892-93  I  passed  at  Leipzig,  studying  at  the  Univer- 
sity. 

In  Yale  College  and  University  I  studied  under  Professors  J. 
D.  Dana,  Brush,  E.  S.  Dana,  A.  W.  Wright,  Newton,  Wells,  Pen- 
field,  and  numerous  others.  In  Athens  I  heard  the  lectures  of 
Drs.  Waldstein  and  Dorpfeld,  and  Profs.  Gardiner  and  Tarbell.  In 
Leipzig  I  have  attended  the  lectures  of  Professors  Overbeck, 
Zirkel,  Wiedemann,  Credner,  Schreiber,  and  Lenk. 

To  all  these  teachers  of  mine  I  owe  the  greatest  thanks,  but 
above  all  to  Professor  E.  S.  Dana  of  New  Haven,  under  whom  for 
three  years  I  studied  mineralogy  and  petrography,  and  to  Geheim- 
rath  Bergrath  Prof.  Dr.  Zirkel,  under  whose  direction  this  paper 
was  written  and  for  whose  friendly  counsel  and  aid  I  feel  deeply 
grateful. 

67 


. 

. 
. 

. 

' 

• 


. 


PLATO  1. 


.  BASALT  F^—  SCHIST 
Hfg-2N.i>PER.    .      El]- LIMESTONE 
I      I- ALLUVIUM. 

SCALE 

,      f      .      f      ,      f * 


PLATE  II. 


FIG.  1.— KI:LA  DEVLIT  FUOM  THE  S.  W.  ;  PIIJKSIK  DEVMT  ON  RIGHT. 


PIG   2.— "KNOLL"  WITH  LAYA  STREAM,  S.  E.  OF  KULA  DEVLIT. 


PLATE  III. 


PLATE  IV. 


FIG.?!.— FROM  S.  Wc~  STREAM,  SHOWING  HORNBLENDE  PARTIALLY  ALTERED 
TO  BROWN  AGGREGATE. 


FIG.  2. — FROM  SECOND  PERIOD  STREAM  (WELL  DIGGING),  SHOWING  HORN- 
BLENDE COMPLETELT  ALTERED  TO  AUGITE  OPACITE  AGGREGATE. 


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